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Timotievich ED, Shilovskiy IP, Khaitov MR. Cell-Penetrating Peptides as Vehicles for Delivery of Therapeutic Nucleic Acids. Mechanisms and Application in Medicine. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:1800-1817. [PMID: 38105200 DOI: 10.1134/s0006297923110111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 09/13/2023] [Accepted: 09/15/2023] [Indexed: 12/19/2023]
Abstract
Currently, nucleic acid therapeutics are actively developed for the treatment and prophylactic of metabolic disorders and oncological, inflammatory, and infectious diseases. A growing number of approved nucleic acid-based drugs evidences a high potential of gene therapy in medicine. Therapeutic nucleic acids act in the cytoplasm, which makes the plasma membrane the main barrier for the penetration of nucleic acid-based drugs into the cell and requires development of special vehicles for their intracellular delivery. The optimal carrier should not only facilitate internalization of nucleic acids, but also exhibit no toxic effects, ensure stabilization of the cargo molecules, and be suitable for a large-scale and low-cost production. Cell-penetrating peptides (CPPs), which match all these requirements, were found to be efficient and low-toxic carriers of nucleic acids. CPPs are typically basic peptides with a positive charge at physiological pH that can form nanostructures with negatively charged nucleic acids. The prospects of CPPs as vehicles for the delivery of therapeutic nucleic acids have been demonstrated in numerous preclinical studies. Some CPP-based drugs had successfully passed clinical trials and were implemented into medical practice. In this review, we described different types of therapeutic nucleic acids and summarized the data on the use of CPPs for their intracellular delivery, as well as discussed, the mechanisms of CPP uptake by the cells, as understanding of these mechanisms can significantly accelerate the development of new gene therapy approaches.
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Affiliation(s)
- Ekaterina D Timotievich
- Institute of Immunology, National Research Center, Federal Medical-Biological Agency of the Russian Federation, Moscow, 115522, Russia
| | - Igor P Shilovskiy
- Institute of Immunology, National Research Center, Federal Medical-Biological Agency of the Russian Federation, Moscow, 115522, Russia.
| | - Musa R Khaitov
- Institute of Immunology, National Research Center, Federal Medical-Biological Agency of the Russian Federation, Moscow, 115522, Russia.
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Khairkhah N, Namvar A, Bolhassani A. Application of Cell Penetrating Peptides as a Promising Drug Carrier to Combat Viral Infections. Mol Biotechnol 2023; 65:1387-1402. [PMID: 36719639 PMCID: PMC9888354 DOI: 10.1007/s12033-023-00679-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 01/20/2023] [Indexed: 02/01/2023]
Abstract
Novel effective drugs or therapeutic vaccines have been already developed to eradicate viral infections. Some non-viral carriers have been used for effective drug delivery to a target cell or tissue. Among them, cell penetrating peptides (CPPs) attracted a special interest to enhance drug delivery into the cells with low toxicity. They were also applied to transfer peptide/protein-based and nucleic acids-based therapeutic vaccines against viral infections. CPPs-conjugated drugs or vaccines were investigated in several viral infections including poliovirus, Ebola, coronavirus, herpes simplex virus, human immunodeficiency virus, hepatitis B virus, hepatitis C virus, Japanese encephalitis virus, and influenza A virus. Some studies showed that the uptake of CPPs or CPPs-conjugated drugs can be performed through both non-endocytic and endocytic pathways. Despite high potential of CPPs for cargo delivery, there are some serious drawbacks such as non-tissue-specificity, instability, and suboptimal pharmacokinetics features that limit their clinical applications. At present, some solutions are utilized to improve the CPPs properties such as conjugation of CPPs with targeting moieties, the use of fusogenic lipids, generation of the proton sponge effect, etc. Up to now, no CPP or composition containing CPPs has been approved by the Food and Drug Administration (FDA) due to the lack of sufficient in vivo studies on stability, immunological assays, toxicity, and endosomal escape of CPPs. In this review, we briefly describe the properties, uptake mechanisms, advantages and disadvantages, and improvement of intracellular delivery, and bioavailability of cell penetrating peptides. Moreover, we focus on their application as an effective drug carrier to combat viral infections.
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Affiliation(s)
- Niloofar Khairkhah
- Department of Hepatitis and AIDS, Pasteur Institute of Iran, Tehran, Iran
| | - Ali Namvar
- Iranian Comprehensive Hemophilia Care Center, Tehran, Iran
| | - Azam Bolhassani
- Department of Hepatitis and AIDS, Pasteur Institute of Iran, Tehran, Iran.
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3
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Tekintaş Y, Temel A. Antisense oligonucleotides: a promising therapeutic option against infectious diseases. NUCLEOSIDES, NUCLEOTIDES & NUCLEIC ACIDS 2023; 43:1-39. [PMID: 37395450 DOI: 10.1080/15257770.2023.2228841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 06/19/2023] [Indexed: 07/04/2023]
Abstract
Infectious diseases have been one of the biggest health problems of humanity for centuries. Nucleic acid-based therapeutics have received attention in recent years with their effectiveness in the treatment of various infectious diseases and vaccine development studies. This review aims to provide a comprehensive understanding of the basic properties underlying the mechanism of antisense oligonucleotides (ASOs), their applications, and their challenges. The efficient delivery of ASOs is the greatest challenge for their therapeutic success, but this problem is overcome with new-generation antisense molecules developed with chemical modifications. The types, carrier molecules, and gene regions targeted by sequences have been summarized in detail. Research and development of antisense therapy is still in its infancy; however, gene silencing therapies appear to have the potential for faster and longer-lasting activity than conventional treatment strategies. On the other hand, realizing the potential of antisense therapy will require a large initial economic investment to ascertain the pharmacological properties and learn how to optimize them. The ability of ASOs to be rapidly designed and synthesized to target different microbes can reduce drug discovery time from 6 years to 1 year. Since ASOs are not particularly affected by resistance mechanisms, they come to the fore in the fight against antimicrobial resistance. The design-based flexibility of ASOs has enabled it to be used for different types of microorganisms/genes and successful in vitro and in vivo results have been revealed. The current review summarized a comprehensive understanding of ASO therapy in combating bacterial and viral infections.
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Affiliation(s)
- Yamaç Tekintaş
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Izmir Katip Celebi University, Izmir, Türkiye
| | - Aybala Temel
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Izmir Katip Celebi University, Izmir, Türkiye
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4
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Jain S, Khaiboullina S, Martynova E, Morzunov S, Baranwal M. Epidemiology of Ebolaviruses from an Etiological Perspective. Pathogens 2023; 12:pathogens12020248. [PMID: 36839520 PMCID: PMC9963726 DOI: 10.3390/pathogens12020248] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/21/2023] [Accepted: 01/29/2023] [Indexed: 02/05/2023] Open
Abstract
Since the inception of the ebolavirus in 1976, 32 outbreaks have resulted in nearly 15,350 deaths in more than ten countries of the African continent. In the last decade, the largest (2013-2016) and second largest (2018-2020) ebolavirus outbreaks have occurred in West Africa (mainly Guinea, Liberia, and Sierra Leone) and the Democratic Republic of the Congo, respectively. The 2013-2016 outbreak indicated an alarming geographical spread of the virus and was the first to qualify as an epidemic. Hence, it is imperative to halt ebolavirus progression and develop effective countermeasures. Despite several research efforts, ebolaviruses' natural hosts and secondary reservoirs still elude the scientific world. The primary source responsible for infecting the index case is also unknown for most outbreaks. In this review, we summarize the history of ebolavirus outbreaks with a focus on etiology, natural hosts, zoonotic reservoirs, and transmission mechanisms. We also discuss the reasons why the African continent is the most affected region and identify steps to contain this virus.
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Affiliation(s)
- Sahil Jain
- Department of Biotechnology, Thapar Institute of Engineering and Technology, Patiala 147004, Punjab, India
- Department of Biochemistry and Molecular Biology, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 6997801, Israel
| | - Svetlana Khaiboullina
- Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008 Kazan, Tatarstan, Russia
| | - Ekaterina Martynova
- Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008 Kazan, Tatarstan, Russia
| | - Sergey Morzunov
- Department of Pathology, School of Medicine, University of Nevada, Reno, NV 89557, USA
- Correspondence: (S.M.); or (M.B.); Tel.: +1-775-682-6230 (S.M.); +91-175-2393118 (M.B.); Fax: +91-175-2364498 (M.B.)
| | - Manoj Baranwal
- Department of Biotechnology, Thapar Institute of Engineering and Technology, Patiala 147004, Punjab, India
- Correspondence: (S.M.); or (M.B.); Tel.: +1-775-682-6230 (S.M.); +91-175-2393118 (M.B.); Fax: +91-175-2364498 (M.B.)
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5
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History and impact of the mouse-adapted Ebola virus model. Antiviral Res 2023; 210:105493. [PMID: 36567023 DOI: 10.1016/j.antiviral.2022.105493] [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: 11/15/2022] [Revised: 12/09/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022]
Abstract
Ebola virus (EBOV) is a member of the filoviridae family, which are comprised of negative sense, enveloped RNA hemorrhagic fever viruses that can cause severe disease and high lethality rates. These viruses require BSL-4 containment laboratories for study. Early studies of EBOV pathogenesis relied heavily on the use of nonhuman primates, which are expensive and cumbersome to handle in large numbers. Guinea pig models were also developed, but even to this day limited reagents are available in this model. In 1998, Mike Bray and colleagues developed a mouse-adapted EBOV (maEBOV) that caused lethality in adult immunocompetent mice. This model had significant advantages, including being inexpensive, allowing for higher animal numbers for statistical analysis, availability of reagents for studying pathogenesis, and availability of a vast array of genetically modified strains. The model has been used to test vaccines, therapeutic drugs, EBOV mutants, and pathogenesis, and its importance is demonstrated by the hundreds of citations referencing the original publication. This review will cover the history of the maEBOV model and its use in filovirus research.
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Antiviral Peptide-Based Conjugates: State of the Art and Future Perspectives. Pharmaceutics 2023; 15:pharmaceutics15020357. [PMID: 36839679 PMCID: PMC9958607 DOI: 10.3390/pharmaceutics15020357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 01/16/2023] [Accepted: 01/17/2023] [Indexed: 01/24/2023] Open
Abstract
Infectious diseases caused by microbial pathogens (bacteria, virus, fungi, parasites) claim millions of deaths per year worldwide and have become a serious challenge to global human health in our century. Viral infections are particularly notable in this regard, not only because humankind is facing some of the deadliest viral pandemics in recent history, but also because the arsenal of drugs to combat the high levels of mutation, and hence the antigenic variability of (mostly RNA) viruses, is disturbingly scarce. Therefore, the search for new antivirals able to successfully fight infection with minimal or no adverse effects on the host is a pressing task. Traditionally, antiviral therapies have relied on relatively small-sized drugs acting as proteases, polymerases, integrase inhibitors, etc. In recent decades, novel approaches involving targeted delivery such as that achieved by peptide-drug conjugates (PDCs) have gained attention as alternative (pro)drugs for tackling viral diseases. Antiviral PDC therapeutics typically involve one or more small drug molecules conjugated to a cell-penetrating peptide (CPP) carrier either directly or through a linker. Such integration of two bioactive elements into a single molecular entity is primarily aimed at achieving improved bioavailability in conditions where conventional drugs are challenged, but may also turn up novel unexpected functionalities and applications. Advances in peptide medicinal chemistry have eased the way to antiviral PDCs, but challenges remain on the way to therapeutic success. In this paper, we review current antiviral CPP-drug conjugates (antiviral PDCs), with emphasis on the types of CPP and antiviral cargo. We integrate the conjugate and the chemical approaches most often applied to combine both entities. Additionally, we comment on various obstacles faced in the design of antiviral PDCs and on the future outlooks for this class of antiviral therapeutics.
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Liu CH, Hu YT, Wong SH, Lin LT. Therapeutic Strategies against Ebola Virus Infection. Viruses 2022; 14:v14030579. [PMID: 35336986 PMCID: PMC8954160 DOI: 10.3390/v14030579] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/03/2022] [Accepted: 03/08/2022] [Indexed: 12/10/2022] Open
Abstract
Since the 2014–2016 epidemic, Ebola virus (EBOV) has spread to several countries and has become a major threat to global health. EBOV is a risk group 4 pathogen, which imposes significant obstacles for the development of countermeasures against the virus. Efforts have been made to develop anti-EBOV immunization and therapeutics, with three vaccines and two antibody-based therapeutics approved in recent years. Nonetheless, the high fatality of Ebola virus disease highlights the need to continuously develop antiviral strategies for the future management of EBOV outbreaks in conjunction with vaccination programs. This review aims to highlight potential EBOV therapeutics and their target(s) of inhibition, serving as a summary of the literature to inform readers of the novel candidates available in the continued search for EBOV antivirals.
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Affiliation(s)
- Ching-Hsuan Liu
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan;
| | - Yee-Tung Hu
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 110, Taiwan;
| | - Shu Hui Wong
- International Ph.D. Program in Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan;
| | - Liang-Tzung Lin
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan;
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 110, Taiwan;
- Correspondence:
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Geng J, Xia X, Teng L, Wang L, Chen L, Guo X, Belingon B, Li J, Feng X, Li X, Shang W, Wan Y, Wang H. Emerging landscape of cell-penetrating peptide-mediated nucleic acid delivery and their utility in imaging, gene-editing, and RNA-sequencing. J Control Release 2022; 341:166-183. [PMID: 34822907 DOI: 10.1016/j.jconrel.2021.11.032] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 11/17/2021] [Accepted: 11/18/2021] [Indexed: 12/11/2022]
Abstract
The safety issues like immunogenicity and unacceptable cancer risk of viral vectors for DNA/mRNA vaccine delivery necessitate the development of non-viral vectors with no toxicity. Among the non-viral strategies, cell-penetrating peptides (CPPs) have been a topic of interest recently because of their ability to cross plasma membranes and facilitate nucleic acids delivery both in vivo and in vitro. In addition to the application in the field of gene vaccine and gene therapy, CPPs based nucleic acids delivery have been proved by its potential application like gene editing, RNA-sequencing, and imaging. Here, we focus on summarizing the recent applications and progress of CPPs-mediated nucleic acids delivery and discuss the current problems and solutions in this field.
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Affiliation(s)
- Jingping Geng
- Department of Microbiology and Immunology, Medical School, China Three Gorges University, Yichang 443002, China; Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, China Three Gorges University, Yichang 443002, China
| | - Xuan Xia
- Department of Physiology and Pathophysiology, Medical School, China Three Gorges University, Yichang 443002, China
| | - Lin Teng
- Department of Cardiovascular Medicine, The First Clinical Medical College of China Three Gorges University, Yichang 443002, China
| | - Lidan Wang
- Department of Microbiology and Immunology, Medical School, China Three Gorges University, Yichang 443002, China; Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, China Three Gorges University, Yichang 443002, China
| | - Linlin Chen
- Department of Microbiology and Immunology, Medical School, China Three Gorges University, Yichang 443002, China; Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, China Three Gorges University, Yichang 443002, China; Affiliated Ren He Hospital of China Three Gorges University, Yichang 443002, China
| | - Xiangli Guo
- Department of Microbiology and Immunology, Medical School, China Three Gorges University, Yichang 443002, China; Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, China Three Gorges University, Yichang 443002, China
| | - Bonn Belingon
- Institute of Cell Engineering, Johns Hopkins University, Baltimore, MD 21210, USA
| | - Jason Li
- Department of Biology, Johns Hopkins University, Baltimore, MD 21210, USA
| | - Xuemei Feng
- Department of Microbiology and Immunology, Medical School, China Three Gorges University, Yichang 443002, China; Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, China Three Gorges University, Yichang 443002, China
| | - Xianghui Li
- Department of Microbiology and Immunology, Medical School, China Three Gorges University, Yichang 443002, China; Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, China Three Gorges University, Yichang 443002, China
| | - Wendou Shang
- Department of Microbiology and Immunology, Medical School, China Three Gorges University, Yichang 443002, China; Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, China Three Gorges University, Yichang 443002, China
| | - Yingying Wan
- Department of Microbiology and Immunology, Medical School, China Three Gorges University, Yichang 443002, China; Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, China Three Gorges University, Yichang 443002, China
| | - Hu Wang
- Department of Microbiology and Immunology, Medical School, China Three Gorges University, Yichang 443002, China.
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Introduction and History of the Chemistry of Nucleic Acids Therapeutics. Methods Mol Biol 2022; 2434:3-31. [PMID: 35213007 PMCID: PMC7612508 DOI: 10.1007/978-1-0716-2010-6_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This introduction charts the history of the development of the major chemical modifications that have influenced the development of nucleic acids therapeutics focusing in particular on antisense oligonucleotide analogues carrying modifications in the backbone and sugar. Brief mention is made of siRNA development and other applications that have by and large utilized the same modifications. We also point out the pitfalls of the use of nucleic acids as drugs, such as their unwanted interactions with pattern recognition receptors, which can be mitigated by chemical modification or used as immunotherapeutic agents.
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10
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Potential of cell-penetrating peptides (CPPs) in delivery of antiviral therapeutics and vaccines. Eur J Pharm Sci 2021; 169:106094. [PMID: 34896590 DOI: 10.1016/j.ejps.2021.106094] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 12/01/2021] [Accepted: 12/02/2021] [Indexed: 12/12/2022]
Abstract
Viral infections are a great threat to human health. Currently, there are no effective vaccines and antiviral drugs against the majority of viral diseases, suggesting the need to develop novel and effective antiviral agents. Since the intracellular delivery of antiviral agents, particularly the impermeable molecules, such as peptides, proteins, and nucleic acids, are essential to exert their therapeutic effects, using a delivery system is highly required. Among various delivery systems, cell-penetrating peptides (CPPs), a group of short peptides with the unique ability of crossing cell membrane, offer great potential for the intracellular delivery of various biologically active cargoes. The results of numerous in vitro and in vivo studies with CPP conjugates demonstrate their promise as therapeutic agents in various medical fields including antiviral therapy. The CPP-mediated delivery of various antiviral agents including peptides, proteins, nucleic acids, and nanocarriers have been associated with therapeutic efficacy both in vitro and in vivo. This review describes various aspects of viruses including their biology, pathogenesis, and therapy and briefly discusses the concept of CPP and its potential in drug delivery. Particularly, it will highlight a variety of CPP applications in the management of viral infections.
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Sandoval-Mojica AF, Altman S, Hunter WB, Pelz-Stelinski KS. Peptide conjugated morpholinos for management of the huanglongbing pathosystem. PEST MANAGEMENT SCIENCE 2020; 76:3217-3224. [PMID: 32358830 DOI: 10.1002/ps.5877] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 04/27/2020] [Accepted: 05/01/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND 'Candidatus Liberibacter asiaticus' (CLas) is the causal agent of the devastating citrus disease Huanglongbing (HLB) and is transmitted by the insect vector Diaphorina citri (Hemiptera: Liviidae). A potential approach for treating CLas infection is the use of synthetic nucleic acid-like oligomers to silence bacterial gene expression. Peptide conjugated morpholinos (PPMOs) targeting essential genes in CLas and the psyllid vector's endosymbiotic bacteria, Wolbachia (-Diaphorina, wDi), were evaluated using in vitro and in vivo assays. RESULTS Expression of the wDi gyrA gene was significantly reduced following incubation of wDi cells with PPMOs. In addition, the viability of isolated wDi cells was greatly reduced when treated with PPMOs as compared to untreated cells. Feeding D. citri adults with a complementary PPMO (CLgyrA-14) showed significantly reduced (70% lower) expression of the CLas gyrA gene. CLas relative density was significantly lower in the psyllids fed with CLgyrA-14, when compared to untreated insects. Psyllids that were treated with CLgyrA-14 were less successful in transmitting the pathogen into uninfected plants, compared to untreated insects. CONCLUSION The expression of essential genes in the D. citri symbiont, wDi and the HLB pathogen were suppressed in response to PPMO treatments. This study demonstrates the potential of PPMOs as a novel strategy for management of bacterial pathogens of fruit trees, such as HLB. © 2020 Society of Chemical Industry.
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Affiliation(s)
- Andrés F Sandoval-Mojica
- Department of Entomology and Nematology, Citrus Research and Education Center, University of Florida, Lake Alfred, FL, USA
| | - Sidney Altman
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT,, USA
| | - Wayne B Hunter
- U.S Department of Agriculture, Agricultural Research Service, Fort Pierce, FL, USA
| | - Kirsten S Pelz-Stelinski
- Department of Entomology and Nematology, Citrus Research and Education Center, University of Florida, Lake Alfred, FL, USA
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Abstract
Oligonucleotides can be used to modulate gene expression via a range of processes including RNAi, target degradation by RNase H-mediated cleavage, splicing modulation, non-coding RNA inhibition, gene activation and programmed gene editing. As such, these molecules have potential therapeutic applications for myriad indications, with several oligonucleotide drugs recently gaining approval. However, despite recent technological advances, achieving efficient oligonucleotide delivery, particularly to extrahepatic tissues, remains a major translational limitation. Here, we provide an overview of oligonucleotide-based drug platforms, focusing on key approaches - including chemical modification, bioconjugation and the use of nanocarriers - which aim to address the delivery challenge.
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13
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Flego M, Frau A, Accardi L, Mallano A, Ascione A, Gellini M, Fanunza E, Vella S, Di Bonito P, Tramontano E. Intracellular human antibody fragments recognizing the VP35 protein of Zaire Ebola filovirus inhibit the protein activity. BMC Biotechnol 2019; 19:64. [PMID: 31488108 PMCID: PMC6727353 DOI: 10.1186/s12896-019-0554-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 08/09/2019] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Ebola hemorrhagic fever is caused by the Ebola filovirus (EBOV), which is one of the most aggressive infectious agents known worldwide. The EBOV pathogenesis starts with uncontrolled viral replication and subversion of both the innate and adaptive host immune response. The multifunctional viral VP35 protein is involved in this process by exerting an antagonistic action against the early antiviral alpha/beta interferon (IFN-α/β) response, and represents a suitable target for the development of strategies to control EBOV infection. Phage display technology permits to select antibodies as single chain Fragment variable (scFv) from an artificial immune system, due to their ability to specifically recognize the antigen of interest. ScFv is ideal for genetic manipulation and to obtain antibody constructs useful for targeting either antigens expressed on cell surface or intracellular antigens if the scFv is expressed as intracellular antibody (intrabody) or delivered into the cells. RESULTS Monoclonal antibodies (mAb) in scFv format specific for the EBOV VP35 were isolated from the ETH-2 library of human recombinant antibodies by phage display technology. Five different clones were identified by sequencing, produced in E.coli and expressed in CHO mammalian cells to be characterized in vitro. All the selected scFvs were able to react with recombinant VP35 protein in ELISA, one of the scFvs being also able to react in Western Blot assay (WB). In addition, all scFvs were expressed in cell cytoplasm as intrabodies; a luciferase reporter gene inhibition assay performed in A549 cells showed that two of the scFvs can significantly hamper the inhibition of the IFN-β-induced RIG-I signaling cascade mediated by EBOV VP35. CONCLUSION Five antibodies in scFv format recognize an active form of EBOV VP35 in ELISA, while one antibody also recognizes VP35 in WB. Two of these scFvs were also able to interfere with the intracellular activity of VP35 in a cell system in vitro. These findings suggest that such antibodies in scFv format might be employed to develop therapeutic molecules able to hamper EBOV infections.
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Affiliation(s)
- Michela Flego
- Istituto Superiore di Sanità (ISS), National Center for Global Health, Viale Regina Elena 299, 00161, Rome, Italy.
| | - Aldo Frau
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato SS554 09042 Monserrato, Cagliari, Italy
| | - Luisa Accardi
- Department of Infectious Diseases, Viral Hepatitis, Oncoviruses and Retroviruses (EVOR) unit, Istituto Superiore di Sanità (ISS), Viale Regina Elena 299, 00161, Rome, Italy
| | - Alessandra Mallano
- Istituto Superiore di Sanità (ISS), National Center for Global Health, Viale Regina Elena 299, 00161, Rome, Italy
| | - Alessandro Ascione
- Istituto Superiore di Sanità (ISS), National Center for Global Health, Viale Regina Elena 299, 00161, Rome, Italy
| | - Mara Gellini
- Istituto Superiore di Sanità (ISS), National Center for Global Health, Viale Regina Elena 299, 00161, Rome, Italy
| | - Elisa Fanunza
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato SS554 09042 Monserrato, Cagliari, Italy
| | - Stefano Vella
- Istituto Superiore di Sanità (ISS), National Center for Global Health, Viale Regina Elena 299, 00161, Rome, Italy
| | - Paola Di Bonito
- Department of Infectious Diseases, Viral Hepatitis, Oncoviruses and Retroviruses (EVOR) unit, Istituto Superiore di Sanità (ISS), Viale Regina Elena 299, 00161, Rome, Italy.
| | - Enzo Tramontano
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato SS554 09042 Monserrato, Cagliari, Italy.
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Dhama K, Karthik K, Khandia R, Chakraborty S, Munjal A, Latheef SK, Kumar D, Ramakrishnan MA, Malik YS, Singh R, Malik SVS, Singh RK, Chaicumpa W. Advances in Designing and Developing Vaccines, Drugs, and Therapies to Counter Ebola Virus. Front Immunol 2018; 9:1803. [PMID: 30147687 PMCID: PMC6095993 DOI: 10.3389/fimmu.2018.01803] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Accepted: 07/23/2018] [Indexed: 01/10/2023] Open
Abstract
Ebola virus (EBOV), a member of the family Filoviridae, is responsible for causing Ebola virus disease (EVD) (formerly named Ebola hemorrhagic fever). This is a severe, often fatal illness with mortality rates varying from 50 to 90% in humans. Although the virus and associated disease has been recognized since 1976, it was only when the recent outbreak of EBOV in 2014-2016 highlighted the danger and global impact of this virus, necessitating the need for coming up with the effective vaccines and drugs to counter its pandemic threat. Albeit no commercial vaccine is available so far against EBOV, a few vaccine candidates are under evaluation and clinical trials to assess their prophylactic efficacy. These include recombinant viral vector (recombinant vesicular stomatitis virus vector, chimpanzee adenovirus type 3-vector, and modified vaccinia Ankara virus), Ebola virus-like particles, virus-like replicon particles, DNA, and plant-based vaccines. Due to improvement in the field of genomics and proteomics, epitope-targeted vaccines have gained top priority. Correspondingly, several therapies have also been developed, including immunoglobulins against specific viral structures small cell-penetrating antibody fragments that target intracellular EBOV proteins. Small interfering RNAs and oligomer-mediated inhibition have also been verified for EVD treatment. Other treatment options include viral entry inhibitors, transfusion of convalescent blood/serum, neutralizing antibodies, and gene expression inhibitors. Repurposed drugs, which have proven safety profiles, can be adapted after high-throughput screening for efficacy and potency for EVD treatment. Herbal and other natural products are also being explored for EVD treatment. Further studies to better understand the pathogenesis and antigenic structures of the virus can help in developing an effective vaccine and identifying appropriate antiviral targets. This review presents the recent advances in designing and developing vaccines, drugs, and therapies to counter the EBOV threat.
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Affiliation(s)
- Kuldeep Dhama
- Division of Pathology, ICAR-Indian Veterinary Research Institute, Bareilly, India
| | - Kumaragurubaran Karthik
- Central University Laboratory, Tamil Nadu Veterinary and Animal Sciences University, Chennai, India
| | - Rekha Khandia
- Department of Biochemistry and Genetics, Barkatullah University, Bhopal, India
| | - Sandip Chakraborty
- Department of Veterinary Microbiology, College of Veterinary Sciences and Animal Husbandry, Agartala, India
| | - Ashok Munjal
- Department of Biochemistry and Genetics, Barkatullah University, Bhopal, India
| | - Shyma K. Latheef
- Immunology Section, ICAR-Indian Veterinary Research Institute, Bareilly, India
| | - Deepak Kumar
- Division of Veterinary Biotechnology, ICAR-Indian Veterinary Research Institute, Bareilly, India
| | | | - Yashpal Singh Malik
- Division of Biological Standardization, ICAR-Indian Veterinary Research Institute, Bareilly, India
| | - Rajendra Singh
- Division of Pathology, ICAR-Indian Veterinary Research Institute, Bareilly, India
| | - Satya Veer Singh Malik
- Division of Veterinary Public Health, ICAR-Indian Veterinary Research Institute, Bareilly, India
| | - Raj Kumar Singh
- ICAR-Indian Veterinary Research Institute, Bareilly, Uttar Pradesh, India
| | - Wanpen Chaicumpa
- Center of Research Excellence on Therapeutic Proteins and Antibody Engineering, Department of Parasitology, Faculty of Medicine SIriraj Hospital, Mahidol University, Bangkok, Thailand
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Nan Y, Zhang YJ. Antisense Phosphorodiamidate Morpholino Oligomers as Novel Antiviral Compounds. Front Microbiol 2018; 9:750. [PMID: 29731743 PMCID: PMC5920040 DOI: 10.3389/fmicb.2018.00750] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 04/03/2018] [Indexed: 01/23/2023] Open
Abstract
Phosphorodiamidate morpholino oligomers (PMO) are short single-stranded DNA analogs that are built upon a backbone of morpholine rings connected by phosphorodiamidate linkages. As uncharged nucleic acid analogs, PMO bind to complementary sequences of target mRNA by Watson–Crick base pairing to block protein translation through steric blockade. PMO interference of viral protein translation operates independently of RNase H. Meanwhile, PMO are resistant to a variety of enzymes present in biologic fluids, a characteristic that makes them highly suitable for in vivo applications. Notably, PMO-based therapy for Duchenne muscular dystrophy (DMD) has been approved by the United States Food and Drug Administration which is now a hallmark for PMO-based antisense therapy. In this review, the development history of PMO, delivery methods for improving cellular uptake of neutrally charged PMO molecules, past studies of PMO antagonism against RNA and DNA viruses, PMO target selection, and remaining questions of PMO antiviral strategies are discussed in detail and new insights are provided.
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Affiliation(s)
- Yuchen Nan
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, China.,Virginia-Maryland College of Veterinary Medicine and Maryland Pathogen Research Institute, University of Maryland, College Park, MD, United States
| | - Yan-Jin Zhang
- Virginia-Maryland College of Veterinary Medicine and Maryland Pathogen Research Institute, University of Maryland, College Park, MD, United States
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16
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An RNA polymerase II-driven Ebola virus minigenome system as an advanced tool for antiviral drug screening. Antiviral Res 2017; 146:21-27. [PMID: 28807685 DOI: 10.1016/j.antiviral.2017.08.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 08/08/2017] [Accepted: 08/09/2017] [Indexed: 11/20/2022]
Abstract
Ebola virus (EBOV) causes a severe disease in humans with the potential for significant international public health consequences. Currently, treatments are limited to experimental vaccines and therapeutics. Therefore, research into prophylaxis and antiviral strategies to combat EBOV infections is of utmost importance. The requirement for high containment laboratories to study EBOV infection is a limiting factor for conducting EBOV research. To overcome this issue, minigenome systems have been used as valuable tools to study EBOV replication and transcription mechanisms and to screen for antiviral compounds at biosafety level 2. The most commonly used EBOV minigenome system relies on the ectopic expression of the T7 RNA polymerase (T7), which can be limiting for certain cell types. We have established an improved EBOV minigenome system that utilizes endogenous RNA polymerase II (pol II) as a driver for the synthesis of minigenome RNA. We show here that this system is as efficient as the T7-based minigenome system, but works in a wider range of cell types, including biologically relevant cell types such as bat cells. Importantly, we were also able to adapt this system to a reliable and cost-effective 96-well format antiviral screening assay with a Z-factor of 0.74, indicative of a robust assay. Using this format, we identified JG40, an inhibitor of Hsp70, as an inhibitor of EBOV replication, highlighting the potential for this system as a tool for antiviral drug screening. In summary, this updated EBOV minigenome system provides a convenient and effective means of advancing the field of EBOV research.
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Bixler SL, Duplantier AJ, Bavari S. Discovering Drugs for the Treatment of Ebola Virus. CURRENT TREATMENT OPTIONS IN INFECTIOUS DISEASES 2017; 9:299-317. [PMID: 28890666 PMCID: PMC5570806 DOI: 10.1007/s40506-017-0130-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Purpose of review Ebola virus, a member of the Filoviridae family, is a causative agent of severe viral hemorrhagic fever in humans. Over the past 40 years, the virus has been linked to several high mortality outbreaks in Africa with the recent West African outbreak resulting in over 11,000 deaths. This review provides a summary of the status of the drug discovery and development process for therapeutics for Ebola virus disease, with a focus on the strategies being used and the challenges facing each stage of the process. Recent findings Despite the wealth of in vitro efficacy data, preclinical data in animal models, and human clinical data, no therapeutics have been approved for the treatment of Ebola virus disease. However, several promising candidates, such as ZMapp and GS-5734, have advanced into ongoing clinical trials. Summary The gravity of the 2014-2016 outbreak spurred a heightened effort to identify and develop new treatments for Ebola virus disease, including small molecules, immunotherapeutics, host factors, and clinical disease management options. Disclaimer Opinions, interpretations, conclusions, and recommendations are those of the authors and are not necessarily endoresed by the U.S. Army.
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Affiliation(s)
- Sandra L Bixler
- United States Army Medical Research Institute of Infectious Diseases, 1425 Porter St, Frederick, MD 21702 USA
| | - Allen J Duplantier
- United States Army Medical Research Institute of Infectious Diseases, 1425 Porter St, Frederick, MD 21702 USA
| | - Sina Bavari
- United States Army Medical Research Institute of Infectious Diseases, 1425 Porter St, Frederick, MD 21702 USA
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18
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Moulton JD. Using Morpholinos to Control Gene Expression. CURRENT PROTOCOLS IN NUCLEIC ACID CHEMISTRY 2017; 68:4.30.1-4.30.29. [PMID: 28252184 PMCID: PMC7162182 DOI: 10.1002/cpnc.21] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Morpholino oligonucleotides are stable, uncharged, water-soluble molecules used to block complementary sequences of RNA, preventing processing, read-through, or protein binding at those sites. Morpholinos are typically used to block translation of mRNA and to block splicing of pre-mRNA, though they can block other interactions between biological macromolecules and RNA. Morpholinos are effective, specific, and lack non-antisense effects. They work in any cell that transcribes and translates RNA, but must be delivered into the nuclear/cytosolic compartment to be effective. Morpholinos form stable base pairs with complementary nucleic acid sequences but apparently do not bind to proteins to a significant extent. They are not recognized by any proteins and do not undergo protein-mediated catalysis-nor do they mediate RNA cleavage by RNase H or the RISC complex. This work focuses on techniques and background for using Morpholinos. © 2017 by John Wiley & Sons, Inc.
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19
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Muñoz-Fontela C, Geisbert TW. The gap between animal and human Ebola virus disease. Future Virol 2017. [DOI: 10.2217/fvl-2016-0128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- César Muñoz-Fontela
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Martinistrasse 52, 20251 Hamburg, Germany
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Bernhard Nocht Strasse 74, 20359 Hamburg, Germany
| | - Thomas W Geisbert
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
- Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX 77555, USA
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20
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Ren JX, Zhang RT, Zhang H, Cao XS, Liu LK, Xie Y. Identification of novel VP35 inhibitors: Virtual screening driven new scaffolds. Biomed Pharmacother 2016; 84:199-207. [DOI: 10.1016/j.biopha.2016.09.034] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Revised: 08/24/2016] [Accepted: 09/11/2016] [Indexed: 11/28/2022] Open
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21
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Integrated Computational Approach for Virtual Hit Identification against Ebola Viral Proteins VP35 and VP40. Int J Mol Sci 2016; 17:ijms17111748. [PMID: 27792169 PMCID: PMC5133775 DOI: 10.3390/ijms17111748] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 09/18/2016] [Accepted: 09/22/2016] [Indexed: 12/30/2022] Open
Abstract
The Ebola virus (EBOV) has been recognised for nearly 40 years, with the most recent EBOV outbreak being in West Africa, where it created a humanitarian crisis. Mortalities reported up to 30 March 2016 totalled 11,307. However, up until now, EBOV drugs have been far from achieving regulatory (FDA) approval. It is therefore essential to identify parent compounds that have the potential to be developed into effective drugs. Studies on Ebola viral proteins have shown that some can elicit an immunological response in mice, and these are now considered essential components of a vaccine designed to protect against Ebola haemorrhagic fever. The current study focuses on chemoinformatic approaches to identify virtual hits against Ebola viral proteins (VP35 and VP40), including protein binding site prediction, drug-likeness, pharmacokinetic and pharmacodynamic properties, metabolic site prediction, and molecular docking. Retrospective validation was performed using a database of non-active compounds, and early enrichment of EBOV actives at different false positive rates was calculated. Homology modelling and subsequent superimposition of binding site residues on other strains of EBOV were carried out to check residual conformations, and hence to confirm the efficacy of potential compounds. As a mechanism for artefactual inhibition of proteins through non-specific compounds, virtual hits were assessed for their aggregator potential compared with previously reported aggregators. These systematic studies have indicated that a few compounds may be effective inhibitors of EBOV replication and therefore might have the potential to be developed as anti-EBOV drugs after subsequent testing and validation in experiments in vivo.
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22
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Hume AJ, Ames J, Rennick LJ, Duprex WP, Marzi A, Tonkiss J, Mühlberger E. Inactivation of RNA Viruses by Gamma Irradiation: A Study on Mitigating Factors. Viruses 2016; 8:v8070204. [PMID: 27455307 PMCID: PMC4974539 DOI: 10.3390/v8070204] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Revised: 07/08/2016] [Accepted: 07/13/2016] [Indexed: 12/21/2022] Open
Abstract
Effective inactivation of biosafety level 4 (BSL-4) pathogens is vital in order to study these agents safely. Gamma irradiation is a commonly used method for the inactivation of BSL-4 viruses, which among other advantages, facilitates the study of inactivated yet morphologically intact virions. The reported values for susceptibility of viruses to inactivation by gamma irradiation are sometimes inconsistent, likely due to differences in experimental protocols. We analyzed the effects of common sample attributes on the inactivation of a recombinant vesicular stomatitis virus expressing the Zaire ebolavirus glycoprotein and green fluorescent protein. Using this surrogate virus, we found that sample volume and protein content of the sample modulated viral inactivation by gamma irradiation but that air volume within the sample container and the addition of external disinfectant surrounding the sample did not. These data identify several factors which alter viral susceptibility to inactivation and highlight the usefulness of lower biosafety level surrogate viruses for such studies. Our results underscore the need to validate inactivation protocols of BSL-4 pathogens using “worst-case scenario” procedures to ensure complete sample inactivation.
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Affiliation(s)
- Adam J Hume
- Department of Microbiology, School of Medicine, Boston University, 620 Albany Street, Boston, MA 02118, USA.
- National Emerging Infectious Diseases Laboratories (NEIDL), Boston University, 620 Albany Street, Boston, MA 02118, USA.
| | - Joshua Ames
- National Emerging Infectious Diseases Laboratories (NEIDL), Boston University, 620 Albany Street, Boston, MA 02118, USA.
| | - Linda J Rennick
- Department of Microbiology, School of Medicine, Boston University, 620 Albany Street, Boston, MA 02118, USA.
- National Emerging Infectious Diseases Laboratories (NEIDL), Boston University, 620 Albany Street, Boston, MA 02118, USA.
| | - W Paul Duprex
- Department of Microbiology, School of Medicine, Boston University, 620 Albany Street, Boston, MA 02118, USA.
- National Emerging Infectious Diseases Laboratories (NEIDL), Boston University, 620 Albany Street, Boston, MA 02118, USA.
| | - Andrea Marzi
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 South 4th St, Hamilton, MT 59840, USA.
| | - John Tonkiss
- National Emerging Infectious Diseases Laboratories (NEIDL), Boston University, 620 Albany Street, Boston, MA 02118, USA.
| | - Elke Mühlberger
- Department of Microbiology, School of Medicine, Boston University, 620 Albany Street, Boston, MA 02118, USA.
- National Emerging Infectious Diseases Laboratories (NEIDL), Boston University, 620 Albany Street, Boston, MA 02118, USA.
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Delayed Time-to-Treatment of an Antisense Morpholino Oligomer Is Effective against Lethal Marburg Virus Infection in Cynomolgus Macaques. PLoS Negl Trop Dis 2016; 10:e0004456. [PMID: 26901785 PMCID: PMC4764691 DOI: 10.1371/journal.pntd.0004456] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 01/22/2016] [Indexed: 11/19/2022] Open
Abstract
Marburg virus (MARV) is an Ebola-like virus in the family Filovirdae that causes sporadic outbreaks of severe hemorrhagic fever with a case fatality rate as high as 90%. AVI-7288, a positively charged antisense phosphorodiamidate morpholino oligomer (PMOplus) targeting the viral nucleoprotein gene, was evaluated as a potential therapeutic intervention for MARV infection following delayed treatment of 1, 24, 48, and 96 h post-infection (PI) in a nonhuman primate lethal challenge model. A total of 30 cynomolgus macaques were divided into 5 groups of 6 and infected with 1,830 plaque forming units of MARV subcutaneously. AVI-7288 was administered by bolus infusion daily for 14 days at 15 mg/kg body weight. Survival was the primary endpoint of the study. While none (0 of 6) of the saline group survived, 83–100% of infected monkeys survived when treatment was initiated 1, 24, 48, or 96 h post-infection (PI). The antisense treatment also reduced serum viremia and inflammatory cytokines in all treatment groups compared to vehicle controls. The antibody immune response to virus was preserved and tissue viral antigen was cleared in AVI-7288 treated animals. These data show that AVI-7288 protects NHPs against an otherwise lethal MARV infection when treatment is initiated up to 96 h PI. Marburg virus (MARV) is a filovirus closely related to Ebola virus and similarly causes hemorrhagic fever in humans. MARV is endemic throughout parts of tropical Africa. Severe outbreaks of Marburg virus disease (MVD) have occurred involving hundreds of human cases. No effective MARV antiviral therapies are available. In this study, we used a positive charged phosphorodiamidate morpholino oligomer (PMOplus) targeting the mRNA of the MARV nucleoprotein gene as a medical countermeasure to treat disease in a lethal nonhuman primate model of MVD. The intravenous treatment regimen was well tolerated with no treatment related adverse effects. We showed that when using this antisense treatment, serum virus levels decreased and 83–100% of the animals survived, even when the treatment was delayed as much as 96 hours after infection. None of the untreated animals survived the viral challenge in this model. Our results suggest that antisense therapies, such as PMOs, hold great promise for the treatment of severe viral diseases such as MVD.
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24
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Ohimain EI. Recent advances in the development of vaccines for Ebola virus disease. Virus Res 2015; 211:174-85. [PMID: 26596227 DOI: 10.1016/j.virusres.2015.10.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 10/11/2015] [Accepted: 10/16/2015] [Indexed: 01/10/2023]
Abstract
Ebola virus is one of the most dangerous microorganisms in the world causing hemorrhagic fevers in humans and non-human primates. Ebola virus (EBOV) is a zoonotic infection, which emerges and re-emerges in human populations. The 2014 outbreak was caused by the Zaire strain, which has a kill rate of up to 90%, though 40% was recorded in the current outbreak. The 2014 outbreak is larger than all 20 outbreaks that have occurred since 1976, when the virus was first discovered. It is the first time that the virus was sustained in urban centers and spread beyond Africa into Europe and USA. Thus far, over 22,000 cases have been reported with about 50% mortality in one year. There are currently no approved therapeutics and preventive vaccines against Ebola virus disease (EVD). Responding to the devastating effe1cts of the 2014 outbreak and the potential risk of global spread, has spurred research for the development of therapeutics and vaccines. This review is therefore aimed at presenting the progress of vaccine development. Results showed that conventional inactivated vaccines produced from EBOV by heat, formalin or gamma irradiation appear to be ineffective. However, novel vaccines production techniques have emerged leading to the production of candidate vaccines that have been demonstrated to be effective in preclinical trials using small animal and non-human primates (NHP) models. Some of the promising vaccines have undergone phase 1 clinical trials, which demonstrated their safety and immunogenicity. Many of the candidate vaccines are vector based such as Vesicular Stomatitis Virus (VSV), Rabies Virus (RABV), Adenovirus (Ad), Modified Vaccinia Ankara (MVA), Cytomegalovirus (CMV), human parainfluenza virus type 3 (HPIV3) and Venezuelan Equine Encephalitis Virus (VEEV). Other platforms include virus like particle (VLP), DNA and subunit vaccines.
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Affiliation(s)
- Elijah Ige Ohimain
- Medical and Public Health Microbiology Research Unit, Biological Sciences Department, Niger Delta University, Wilberforce Island, Bayelsa State, Nigeria.
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25
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Abstract
Global outbreaks of diseases caused by zoonotic viruses have steadily increased in recent years. Emerging zoonotic viruses are generally phylogenetically diverse, are unpredictable and are known to cause diseases with high case fatality rates in humans and are hard to protect against due to lack of approved antiviral drugs. The aim of this review is to discuss how advances in genomics, rational drug design and innate immune signaling can contribute to the design of nucleic acid-based drugs to combat these emerging threats. Specifically, the antiviral activity of siRNAs, antisense oligonucleotides is mediated by sequence-specific gene silencing, and broad-spectrum innate and antiviral immune responses can be elicited by toll-like receptor agonists. This review will summarize their current state of development, safety and efficacy, and provide perspectives on future development.
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26
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Kiselev OI, Vasin AV, Shevyryova MP, Deeva EG, Sivak KV, Egorov VV, Tsvetkov VB, Egorov AY, Romanovskaya-Romanko EA, Stepanova LA, Komissarov AB, Tsybalova LM, Ignatjev GM. Ebola hemorrhagic fever: Properties of the pathogen and development of vaccines and chemotherapeutic agents. Mol Biol 2015; 49:480-493. [PMID: 32214474 PMCID: PMC7089462 DOI: 10.1134/s002689331504007x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 01/16/2015] [Indexed: 11/22/2022]
Abstract
Ebola hemorrhagic fever (EHF) epidemic currently ongoing in West Africa is not the first among numerous epidemics in the continent. Yet it seems to be the worst EHF epidemic outbreak caused by Ebola virus Zaire since 1976 as regards its extremely large scale and rapid spread in the population. Experiments to study the agent have continued for more than 20 years. The EHF virus has a relatively simple genome with seven genes and additional reading frame resulting from RNA editing. While being of a relatively low genetic capacity, the virus can be ranked as a standard for pathogenicity with the ability to evade the host immune response in uttermost perfection. The EHF virus has similarities with retroviruses, but belongs to (-)RNA viruses of a nonretroviral origin. Genetic elements of the virus, NIRV, were detected in animal and human genomes. EHF virus glycoprotein (GP) is a class I fusion protein and shows more similarities than distinctions in tertiary structure with SIV and HIV gp41 proteins and even influenza virus hemagglutinin. EHF is an unusual infectious disease, and studying the molecular basis of its pathogenesis may contribute to new findings in therapy of severe conditions leading to a fatal outcome.
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Affiliation(s)
- O. I. Kiselev
- Institute of Influenza, Ministry of Health of the Russian Federation, St. Petersburg, 197376 Russia
| | - A. V. Vasin
- Institute of Influenza, Ministry of Health of the Russian Federation, St. Petersburg, 197376 Russia
- St. Petersburg State Polytechnic University, St. Petersburg, 195251 Russia
| | - M. P. Shevyryova
- Ministry of Health of the Russian Federation, Moscow, 127994 Russia
| | - E. G. Deeva
- Institute of Influenza, Ministry of Health of the Russian Federation, St. Petersburg, 197376 Russia
| | - K. V. Sivak
- Institute of Influenza, Ministry of Health of the Russian Federation, St. Petersburg, 197376 Russia
| | - V. V. Egorov
- Institute of Influenza, Ministry of Health of the Russian Federation, St. Petersburg, 197376 Russia
| | - V. B. Tsvetkov
- Institute of Influenza, Ministry of Health of the Russian Federation, St. Petersburg, 197376 Russia
- Topchiev Institute of Petrochemical Synthesis, Moscow, 119991 Russia
| | - A. Yu. Egorov
- Institute of Influenza, Ministry of Health of the Russian Federation, St. Petersburg, 197376 Russia
| | | | - L. A. Stepanova
- Institute of Influenza, Ministry of Health of the Russian Federation, St. Petersburg, 197376 Russia
| | - A. B. Komissarov
- Institute of Influenza, Ministry of Health of the Russian Federation, St. Petersburg, 197376 Russia
| | - L. M. Tsybalova
- Institute of Influenza, Ministry of Health of the Russian Federation, St. Petersburg, 197376 Russia
| | - G. M. Ignatjev
- Institute of Influenza, Ministry of Health of the Russian Federation, St. Petersburg, 197376 Russia
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27
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Lam S, Chen H, Chen CK, Min N, Chu JJH. Antiviral Phosphorodiamidate Morpholino Oligomers are Protective against Chikungunya Virus Infection on Cell-based and Murine Models. Sci Rep 2015. [PMID: 26224141 PMCID: PMC4649900 DOI: 10.1038/srep12727] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Chikungunya virus (CHIKV) infection in human is associated with debilitating and persistent arthralgia and arthritis. Currently, there is no specific vaccine or effective antiviral available. Anti-CHIKV Phosphorodiamidate Morpholino Oligomer (CPMO) was evaluated for its antiviral efficacy and cytotoxcity in human cells and neonate murine model. Two CPMOs were designed to block translation initiation of a highly conserved sequence in CHIKV non-structural and structural polyprotein, respectively. Pre-treatment of HeLa cells with CPMO1 significantly suppressed CHIKV titre, CHIKV E2 protein expression and prevented CHIKV-induced CPE. CPMO1 activity was also CHIKV-specific as shown by the lack of cross-reactivity against SINV or DENV replication. When administered prophylactically in neonate mice, 15 μg/g CPMO1v conferred 100% survival against CHIKV disease. In parallel, these mice demonstrated significant reduction in viremia and viral load in various tissues. Immunohistological examination of skeletal muscles and liver of CPMO1v-treated mice also showed healthy tissue morphology, in contrast to evident manifestation of CHIKV pathogenesis in PBS- or scrambled sCPMO1v-treated groups. Taken together, our findings highlight for the first time that CPMO1v has strong protective effect against CHIKV infection. This warrants future development of morpholino as an alternative antiviral agent to address CHIKV infection in clinical applications.
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Affiliation(s)
- Shirley Lam
- Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore
| | - Huixin Chen
- Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore
| | - Caiyun Karen Chen
- Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore
| | - Nyo Min
- Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore
| | - Justin Jang Hann Chu
- Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore
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Janeba Z. Development of Small-Molecule Antivirals for Ebola. Med Res Rev 2015; 35:1175-94. [PMID: 26172225 PMCID: PMC7168439 DOI: 10.1002/med.21355] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 05/21/2015] [Accepted: 05/23/2015] [Indexed: 01/05/2023]
Abstract
Ebola hemorrhagic fever is a deadly disease caused by infection with one of the Ebola virus species. Although a significant progress has recently been made in understanding of Ebola virus biology and pathogenesis, development of effective anti-Ebola treatments has not been very productive, compared to other areas of antiviral research (e.g., HIV and HCV infections). No approved vaccine or medicine is available for Ebola but several are currently under development. This review summarises attempts in identification, evaluation, and development of small-molecule candidates for treatment of Ebola viral disease, including the most promising experimental drugs brincidofovir (CMX001), BCX4430, and favipiravir (T-705).
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Affiliation(s)
- Zlatko Janeba
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i. Flemingovo nám. 2, CZ-16610 Prague 6, Czech Republic
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Shurtleff AC, Whitehouse CA, Ward MD, Cazares LH, Bavari S. Pre-symptomatic diagnosis and treatment of filovirus diseases. Front Microbiol 2015; 6:108. [PMID: 25750638 PMCID: PMC4335271 DOI: 10.3389/fmicb.2015.00108] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 01/28/2015] [Indexed: 01/01/2023] Open
Abstract
Filoviruses are virulent human pathogens which cause severe illness with high case fatality rates and for which there are no available FDA-approved vaccines or therapeutics. Diagnostic tools including antibody- and molecular-based assays, mass spectrometry, and next-generation sequencing are continually under development. Assays using the polymerase chain reaction (PCR) have become the mainstay for the detection of filoviruses in outbreak settings. In many cases, real-time reverse transcriptase-PCR allows for the detection of filoviruses to be carried out with minimal manipulation and equipment and can provide results in less than 2 h. In cases of novel, highly diverse filoviruses, random-primed pyrosequencing approaches have proved useful. Ideally, diagnostic tests would allow for diagnosis of filovirus infection as early as possible after infection, either before symptoms begin, in the event of a known exposure or epidemiologic outbreak, or post-symptomatically. If tests could provide an early definitive diagnosis, then this information may be used to inform the choice of possible therapeutics. Several exciting new candidate therapeutics have been described recently; molecules that have therapeutic activity when administered to animal models of infection several days post-exposure, once signs of disease have begun. The latest data for candidate nucleoside analogs, small interfering RNA (siRNA) molecules, phosphorodiamidate (PMO) molecules, as well as antibody and blood-product therapeutics and therapeutic vaccines are discussed. For filovirus researchers and government agencies interested in making treatments available for a nation's defense as well as its general public, having the right diagnostic tools to identify filovirus infections, as well as a panel of available therapeutics for treatment when needed, is a high priority. Additional research in both areas is required for ultimate success, but significant progress is being made to reach these goals.
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Affiliation(s)
- Amy C Shurtleff
- Molecular and Translational Sciences Division, United States Army Medical Research Institute of Infectious Diseases Fort Detrick, MD, USA
| | - Chris A Whitehouse
- Molecular and Translational Sciences Division, United States Army Medical Research Institute of Infectious Diseases Fort Detrick, MD, USA
| | - Michael D Ward
- Molecular and Translational Sciences Division, United States Army Medical Research Institute of Infectious Diseases Fort Detrick, MD, USA
| | - Lisa H Cazares
- Molecular and Translational Sciences Division, United States Army Medical Research Institute of Infectious Diseases Fort Detrick, MD, USA
| | - Sina Bavari
- Molecular and Translational Sciences Division, United States Army Medical Research Institute of Infectious Diseases Fort Detrick, MD, USA
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Kilgore PE, Grabenstein JD, Salim AM, Rybak M. Treatment of Ebola Virus Disease. Pharmacotherapy 2015; 35:43-53. [DOI: 10.1002/phar.1545] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Paul E. Kilgore
- Department of Pharmacy Practice; Eugene Applebaum College of Pharmacy and Health Sciences; Wayne State University; Detroit Michigan
| | | | - Abdulbaset M. Salim
- Department of Pharmacy Practice; Eugene Applebaum College of Pharmacy and Health Sciences; Wayne State University; Detroit Michigan
| | - Michael Rybak
- Department of Pharmacy Practice; Eugene Applebaum College of Pharmacy and Health Sciences; Wayne State University; Detroit Michigan
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Patrick Reid S, Shurtleff AC, Costantino JA, Tritsch SR, Retterer C, Spurgers KB, Bavari S. HSPA5 is an essential host factor for Ebola virus infection. Antiviral Res 2014; 109:171-4. [DOI: 10.1016/j.antiviral.2014.07.004] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 07/01/2014] [Accepted: 07/03/2014] [Indexed: 11/26/2022]
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Binning JM, Wang T, Luthra P, Shabman RS, Borek DM, Liu G, Xu W, Leung DW, Basler CF, Amarasinghe GK. Development of RNA aptamers targeting Ebola virus VP35. Biochemistry 2013; 52:8406-19. [PMID: 24067086 DOI: 10.1021/bi400704d] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Viral protein 35 (VP35), encoded by filoviruses, is a multifunctional dsRNA binding protein that plays important roles in viral replication, innate immune evasion, and pathogenesis. The multifunctional nature of these proteins also presents opportunities to develop countermeasures that target distinct functional regions. However, functional validation and the establishment of therapeutic approaches toward such multifunctional proteins, particularly for nonenzymatic targets, are often challenging. Our previous work on filoviral VP35 proteins defined conserved basic residues located within its C-terminal dsRNA binding interferon (IFN) inhibitory domain (IID) as important for VP35 mediated IFN antagonism and viral polymerase cofactor functions. In the current study, we used a combination of structural and functional data to determine regions of Ebola virus (EBOV) VP35 (eVP35) to target for aptamer selection using SELEX. Select aptamers, representing, two distinct classes, were further characterized based on their interaction properties to eVP35 IID. These results revealed that these aptamers bind to distinct regions of eVP35 IID with high affinity (10-50 nM) and specificity. These aptamers can compete with dsRNA for binding to eVP35 and disrupt the eVP35-nucleoprotein (NP) interaction. Consistent with the ability to antagonize the eVP35-NP interaction, select aptamers can inhibit the function of the EBOV polymerase complex reconstituted by the expression of select viral proteins. Taken together, our results support the identification of two aptamers that bind filoviral VP35 proteins with high affinity and specificity and have the capacity to potentially function as filoviral VP35 protein inhibitors.
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Affiliation(s)
- Jennifer M Binning
- Department of Pathology and Immunology, Washington University School of Medicine , St. Louis, Missouri 63110, United States
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Abstract
Zoonotic transmission of Ebola virus (EBOV) to humans causes a severe haemorrhagic fever in afflicted individuals with high case-fatality rates. Neither vaccines nor therapeutics are at present available to combat EBOV infection, making the virus a potential threat to public health. To devise antiviral strategies, it is important to understand which components of the immune system could be effective against EBOV infection. The interferon (IFN) system constitutes a key innate defence against viral infections and prevents development of lethal disease in mice infected with EBOV strains not adapted to this host. Recent research revealed that expression of the host cell IFN-inducible transmembrane proteins 1-3 (IFITM1-3) and tetherin is induced by IFN and restricts EBOV infection, at least in cell culture model systems. IFITMs, tetherin and other effector molecules of the IFN system could thus pose a potent barrier against EBOV spread in humans. However, EBOV interferes with signalling events required for human cells to express these proteins. Here, we will review the strategies employed by EBOV to fight the IFN system, and we will discuss how IFITM proteins and tetherin inhibit EBOV infection.
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Affiliation(s)
- A Kühl
- Institute of Virology, Hannover Medical School, Hannover, Germany.
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Use of the Syrian hamster as a new model of ebola virus disease and other viral hemorrhagic fevers. Viruses 2012; 4:3754-84. [PMID: 23242370 PMCID: PMC3528289 DOI: 10.3390/v4123754] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 12/10/2012] [Accepted: 12/12/2012] [Indexed: 01/01/2023] Open
Abstract
Historically, mice and guinea pigs have been the rodent models of choice for therapeutic and prophylactic countermeasure testing against Ebola virus disease (EVD). Recently, hamsters have emerged as a novel animal model for the in vivo study of EVD. In this review, we discuss the history of the hamster as a research laboratory animal, as well as current benefits and challenges of this model. Availability of immunological reagents is addressed. Salient features of EVD in hamsters, including relevant pathology and coagulation parameters, are compared directly with the mouse, guinea pig and nonhuman primate models.
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Abstract
Filoviruses, marburgvirus (MARV) and ebolavirus (EBOV), are causative agents of highly lethal hemorrhagic fever in humans. MARV and EBOV share a common genome organization but show important differences in replication complex formation, cell entry, host tropism, transcriptional regulation, and immune evasion. Multifunctional filoviral viral protein (VP) 35 proteins inhibit innate immune responses. Recent studies suggest double-stranded (ds)RNA sequestration is a potential mechanism that allows EBOV VP35 to antagonize retinoic-acid inducible gene-I (RIG-I) like receptors (RLRs) that are activated by viral pathogen-associated molecular patterns (PAMPs), such as double-strandedness and dsRNA blunt ends. Here, we show that MARV VP35 can inhibit IFN production at multiple steps in the signaling pathways downstream of RLRs. The crystal structure of MARV VP35 IID in complex with 18-bp dsRNA reveals that despite the similar protein fold as EBOV VP35 IID, MARV VP35 IID interacts with the dsRNA backbone and not with blunt ends. Functional studies show that MARV VP35 can inhibit dsRNA-dependent RLR activation and interferon (IFN) regulatory factor 3 (IRF3) phosphorylation by IFN kinases TRAF family member-associated NFkb activator (TANK) binding kinase-1 (TBK-1) and IFN kB kinase e (IKKe) in cell-based studies. We also show that MARV VP35 can only inhibit RIG-I and melanoma differentiation associated gene 5 (MDA5) activation by double strandedness of RNA PAMPs (coating backbone) but is unable to inhibit activation of RLRs by dsRNA blunt ends (end capping). In contrast, EBOV VP35 can inhibit activation by both PAMPs. Insights on differential PAMP recognition and inhibition of IFN induction by a similar filoviral VP35 fold, as shown here, reveal the structural and functional plasticity of a highly conserved virulence factor.
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Iversen PL, Warren TK, Wells JB, Garza NL, Mourich DV, Welch LS, Panchal RG, Bavari S. Discovery and early development of AVI-7537 and AVI-7288 for the treatment of Ebola virus and Marburg virus infections. Viruses 2012; 4:2806-30. [PMID: 23202506 PMCID: PMC3509674 DOI: 10.3390/v4112806] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 10/02/2012] [Accepted: 10/02/2012] [Indexed: 11/28/2022] Open
Abstract
There are no currently approved treatments for filovirus infections. In this study we report the discovery process which led to the development of antisense Phosphorodiamidate Morpholino Oligomers (PMOs) AVI-6002 (composed of AVI-7357 and AVI-7539) and AVI-6003 (composed of AVI-7287 and AVI-7288) targeting Ebola virus and Marburg virus respectively. The discovery process involved identification of optimal transcript binding sites for PMO based RNA-therapeutics followed by screening for effective viral gene target in mouse and guinea pig models utilizing adapted viral isolates. An evolution of chemical modifications were tested, beginning with simple Phosphorodiamidate Morpholino Oligomers (PMO) transitioning to cell penetrating peptide conjugated PMOs (PPMO) and ending with PMOplus containing a limited number of positively charged linkages in the PMO structure. The initial lead compounds were combinations of two agents targeting separate genes. In the final analysis, a single agent for treatment of each virus was selected, AVI-7537 targeting the VP24 gene of Ebola virus and AVI-7288 targeting NP of Marburg virus, and are now progressing into late stage clinical development as the optimal therapeutic candidates.
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MESH Headings
- Animals
- Antiviral Agents/administration & dosage
- Antiviral Agents/chemistry
- Base Sequence
- Ebolavirus/genetics
- Ebolavirus/metabolism
- Genes, Viral
- Guinea Pigs
- Hemorrhagic Fever, Ebola/mortality
- Hemorrhagic Fever, Ebola/therapy
- Hemorrhagic Fever, Ebola/virology
- Marburg Virus Disease/mortality
- Marburg Virus Disease/therapy
- Marburg Virus Disease/virology
- Marburgvirus/genetics
- Marburgvirus/metabolism
- Mice
- Morpholinos/administration & dosage
- Morpholinos/chemistry
- Oligodeoxyribonucleotides, Antisense/administration & dosage
- Oligodeoxyribonucleotides, Antisense/chemistry
- Primates
- Protein Biosynthesis/genetics
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Viral/genetics
- RNA, Viral/metabolism
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Affiliation(s)
| | - Travis K. Warren
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland 21702, USA; (T.K.W.); (J.B.W.); (N.L.G.); (L.S.W.); (S.B.); (R.P.)
| | - Jay B. Wells
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland 21702, USA; (T.K.W.); (J.B.W.); (N.L.G.); (L.S.W.); (S.B.); (R.P.)
| | - Nicole L. Garza
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland 21702, USA; (T.K.W.); (J.B.W.); (N.L.G.); (L.S.W.); (S.B.); (R.P.)
| | - Dan V. Mourich
- Sarepta Therapeutics, Bothell, Washington 98021, USA; (P.L.I.); (D.V.M)
| | - Lisa S. Welch
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland 21702, USA; (T.K.W.); (J.B.W.); (N.L.G.); (L.S.W.); (S.B.); (R.P.)
| | - Rekha G. Panchal
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland 21702, USA; (T.K.W.); (J.B.W.); (N.L.G.); (L.S.W.); (S.B.); (R.P.)
| | - Sina Bavari
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland 21702, USA; (T.K.W.); (J.B.W.); (N.L.G.); (L.S.W.); (S.B.); (R.P.)
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Shurtleff AC, Warren TK, Bavari S. Nonhuman primates as models for the discovery and development of ebolavirus therapeutics. Expert Opin Drug Discov 2012; 6:233-50. [PMID: 22647202 DOI: 10.1517/17460441.2011.554815] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Ebolaviruses are human pathogenic Category A priority pathogens for which no vaccines or therapeutics are currently licensed; however, several therapeutic agents have shown promising efficacy in nonhuman primate models of infection and are potential candidates for use in humans. Demonstration of efficacy in nonhuman primate models of ebolavirus infection will probably be central to the development and eventual licensure of ebolavirus medical countermeasures given the ethical and feasibility constraints of human efficacy assessments. AREAS COVERED The authors describe ebolavirus hemorrhagic fever (EHF), with an emphasis on comparing human and nonhuman primate pathophysiology. Published data examining human and animal clinical disease parameters, histopathological findings, and immune responses in fatal and nonfatal cases are synthesized and evaluated. Importantly, the authors also introduce and describe the FDA Animal Efficacy Rule as well as recent advances in antiviral drug development strategies for the treatment of EHF. EXPERT OPINION Well-characterized models of ebolavirus infection are currently under development and scrutiny as to their accuracy and utility for modeling fatal infection in humans. The advanced development and eventual licensure of therapeutic agents will require demonstration that mechanisms conferring protection in nonhuman primate models of infection are predictive of protective responses in humans.
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Affiliation(s)
- Amy C Shurtleff
- US Army Medical Research Institute of Infectious Diseases, Integrated Toxicology Division, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA +1 301 619 4246 ; +1 541 754 3545 ;
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Friedrich BM, Trefry JC, Biggins JE, Hensley LE, Honko AN, Smith DR, Olinger GG. Potential vaccines and post-exposure treatments for filovirus infections. Viruses 2012; 4:1619-50. [PMID: 23170176 PMCID: PMC3499823 DOI: 10.3390/v4091619] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 08/31/2012] [Accepted: 09/04/2012] [Indexed: 01/07/2023] Open
Abstract
Viruses of the family Filoviridae represent significant health risks as emerging infectious diseases as well as potentially engineered biothreats. While many research efforts have been published offering possibilities toward the mitigation of filoviral infection, there remain no sanctioned therapeutic or vaccine strategies. Current progress in the development of filovirus therapeutics and vaccines is outlined herein with respect to their current level of testing, evaluation, and proximity toward human implementation, specifically with regard to human clinical trials, nonhuman primate studies, small animal studies, and in vitro development. Contemporary methods of supportive care and previous treatment approaches for human patients are also discussed.
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Affiliation(s)
- Brian M. Friedrich
- United States Army Medical Research Institute of Infectious Diseases, Division of Virology, 1425 Porter Street, Frederick, MD 21702, USA; (B.M.F.); (J.C.T.); (J.E.B.); (A.N.H.); (D.R.S.)
| | - John C. Trefry
- United States Army Medical Research Institute of Infectious Diseases, Division of Virology, 1425 Porter Street, Frederick, MD 21702, USA; (B.M.F.); (J.C.T.); (J.E.B.); (A.N.H.); (D.R.S.)
| | - Julia E. Biggins
- United States Army Medical Research Institute of Infectious Diseases, Division of Virology, 1425 Porter Street, Frederick, MD 21702, USA; (B.M.F.); (J.C.T.); (J.E.B.); (A.N.H.); (D.R.S.)
| | - Lisa E. Hensley
- United States Food and Drug Administration (FDA), Medical Science Countermeasures Initiative (McMi), 10903 New Hampshire Avenue, Silver Spring, MD 20901, USA; (L.E.H.)
| | - Anna N. Honko
- United States Army Medical Research Institute of Infectious Diseases, Division of Virology, 1425 Porter Street, Frederick, MD 21702, USA; (B.M.F.); (J.C.T.); (J.E.B.); (A.N.H.); (D.R.S.)
| | - Darci R. Smith
- United States Army Medical Research Institute of Infectious Diseases, Division of Virology, 1425 Porter Street, Frederick, MD 21702, USA; (B.M.F.); (J.C.T.); (J.E.B.); (A.N.H.); (D.R.S.)
| | - Gene G. Olinger
- United States Army Medical Research Institute of Infectious Diseases, Division of Virology, 1425 Porter Street, Frederick, MD 21702, USA; (B.M.F.); (J.C.T.); (J.E.B.); (A.N.H.); (D.R.S.)
- Author to whom correspondence should be addressed; (G.G.O.); Tel.: +1-301-619-8581; +1-301-619-2290
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Bradfute SB, Warfield KL, Bray M. Mouse models for filovirus infections. Viruses 2012; 4:1477-508. [PMID: 23170168 PMCID: PMC3499815 DOI: 10.3390/v4091477] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 08/27/2012] [Accepted: 08/27/2012] [Indexed: 12/21/2022] Open
Abstract
The filoviruses marburg- and ebolaviruses can cause severe hemorrhagic fever (HF) in humans and nonhuman primates. Because many cases have occurred in geographical areas lacking a medical research infrastructure, most studies of the pathogenesis of filoviral HF, and all efforts to develop drugs and vaccines, have been carried out in biocontainment laboratories in non-endemic countries, using nonhuman primates (NHPs), guinea pigs and mice as animal models. NHPs appear to closely mirror filoviral HF in humans (based on limited clinical data), but only small numbers may be used in carefully regulated experiments; much research is therefore done in rodents. Because of their availability in large numbers and the existence of a wealth of reagents for biochemical and immunological testing, mice have become the preferred small animal model for filovirus research. Since the first experiments following the initial 1967 marburgvirus outbreak, wild-type or mouse-adapted viruses have been tested in immunocompetent or immunodeficient mice. In this paper, we review how these types of studies have been used to investigate the pathogenesis of filoviral disease, identify immune responses to infection and evaluate antiviral drugs and vaccines. We also discuss the strengths and weaknesses of murine models for filovirus research, and identify important questions for further study.
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Affiliation(s)
- Steven B. Bradfute
- Molecular Genetics and Microbiology, University of New Mexico, Albuquerque, NM 87131, USA
- Author to whom correspondence should be addressed; ; Tel.: +1-505-272-1433; Fax: +1-505-272-6995
| | - Kelly L. Warfield
- Vaccine Development, Integrated Biotherapeutics, Inc., Gaithersburg, MD 20878, USA;
| | - Mike Bray
- Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA;
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40
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Therapeutic delivery opportunities, obstacles and applications for cell-penetrating peptides. Ther Deliv 2012; 2:71-82. [PMID: 22833926 DOI: 10.4155/tde.10.78] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Advancements in the development of large bioactive molecules as therapeutic agents have made drug delivery an active and important field of research. Cell-penetrating peptides (CPPs) have the ability to deliver an array of molecules and even nano-size particles into cells in an efficient and non-toxic manner, both in vitro and in vivo. This review aims to give a perspective on the obstacles that CPP-mediated drug delivery is currently facing as well as the great opportunities for improvements that lie ahead. Strategies for delivery of novel gene-modulating agents and enhancing efficacy of classical drugs will be discussed, as well as methods for increasing bioavailability and tissue specificity of CPPs. The usefulness and potential of CPPs as therapeutic drug-delivery vectors will be exemplified by their use in the treatment of cancer, viral infection and muscular dystrophy.
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Shurtleff AC, Nguyen TL, Kingery DA, Bavari S. Therapeutics for filovirus infection: traditional approaches and progress towards in silico drug design. Expert Opin Drug Discov 2012; 7:935-54. [PMID: 22873527 DOI: 10.1517/17460441.2012.714364] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Ebolaviruses and marburgviruses cause severe and often lethal human hemorrhagic fevers. As no FDA-approved therapeutics are available for these infections, efforts to discover new therapeutics are important, especially because these pathogens are considered biothreats and emerging infectious diseases. All methods for discovering new therapeutics should be considered, including compound library screening in vitro against virus and in silico structure-based drug design, where possible, if sufficient biochemical and structural information is available. AREAS COVERED This review covers the structure and function of filovirus proteins, as they have been reported to date, as well as some of the current antiviral screening approaches. The authors discuss key studies mapping small-molecule modulators that were found through library and in silico screens to potential sites on viral proteins or host proteins involved in virus trafficking and pathogenesis. A description of ebolavirus and marburgvirus diseases and available animal models is also presented. EXPERT OPINION To discover novel therapeutics with potent efficacy using sophisticated computational methods, more high-resolution crystal structures of filovirus proteins and more details about the protein functions and host interaction will be required. Current compound screening efforts are finding active antiviral compounds, but an emphasis on discovery research to investigate protein structures and functions enabling in silico drug design would provide another avenue for finding antiviral molecules. Additionally, targeting of protein-protein interactions may be a future avenue for drug discovery since disrupting catalytic sites may not be possible for all proteins.
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Affiliation(s)
- Amy C Shurtleff
- U.S. Army Medical Research Institute of Infectious Diseases, Integrated Toxicology Division, Fort Detrick, 1425 Porter Street, Frederick, MD 21702, USA.
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Warren TK, Shurtleff AC, Bavari S. Advanced morpholino oligomers: a novel approach to antiviral therapy. Antiviral Res 2012; 94:80-8. [PMID: 22353544 PMCID: PMC7114334 DOI: 10.1016/j.antiviral.2012.02.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Revised: 01/31/2012] [Accepted: 02/01/2012] [Indexed: 01/21/2023]
Abstract
Phosphorodiamidate morpholino oligomers (PMOs) are synthetic antisense oligonucleotide analogs that are designed to interfere with translational processes by forming base-pair duplexes with specific RNA sequences. Positively charged PMOs (PMOplus™) are effective for the postexposure protection of two fulminant viral diseases, Ebola and Marburg hemorrhagic fever in nonhuman primates, and this class of antisense agent may also have possibilities for treatment of other viral diseases. PMOs are highly stable, are effective by a variety of routes of administration, can be readily formulated in common isotonic delivery vehicles, and can be rapidly designed and synthesized. These are properties which may make PMOs good candidates for use during responses to emerging or reemerging viruses that may be insensitive to available therapies or for use during outbreaks, especially in regions that lack a modern medical infrastructure. While the efficacy of sequence-specific therapies can be limited by target-site sequence variations that occur between variants or by the emergence of resistant mutants during infections, various PMO design strategies can minimize these impacts. These strategies include the use of promiscuous bases such as inosine to compensate for predicted base-pair mismatches, the use of sequences that target conserved sites between viral strains, and the use of sequences that target host products that viruses utilize for infection.
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Affiliation(s)
| | | | - Sina Bavari
- Corresponding author. Tel.: +1 301 619 4246.
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43
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Zhang YJ, Patel D, Nan Y, Fan S. Inhibition of primary effusion lymphoma engraftment in SCID mice by morpholino oligomers against early lytic genes of Kaposi's sarcoma-associated herpesvirus. Antivir Ther 2012; 16:657-66. [PMID: 21817187 DOI: 10.3851/imp1810] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
BACKGROUND Kaposi's sarcoma-associated herpesvirus (KSHV) is associated with several malignant diseases, including Kaposi's sarcoma, primary effusion lymphoma (PEL) and multicentric Castleman's disease. The objectives of this study were to investigate the use of peptide-conjugated phosphorodiamidate morpholino oligomers (PPMOs) against KSHV early lytic genes and to assess their efficacy in severe combined immunodeficiency disease (SCID) mice against PEL engraftment. PPMOs are short, single-stranded DNA analogues that contain a backbone of morpholine rings and phosphorodiamidate linkages and have high delivery efficiency into cells. METHODS PEL cells were treated with PPMOs against viral interferon regulatory factor 1 (vIRF-1) and expression of vIRF-1 was analysed. PPMOs against vIRF-1 and viral interleukin-6 (vIL-6) were evaluated against PEL cell engraftment in SCID mice. The PPMOs were incubated with BCBL-1 cells and then introduced into the peritoneal cavities of SCID mice, followed by 9 more doses of PPMOs administered at 2-day intervals. At weeks 3 and 9 after BCBL-1 delivery, peritoneal lavage was collected and the ratio of PEL cells among total cells was determined by flow cytometry analysis. RESULTS Treatment of PEL cells with PPMOs against vIRF-1 led to a reduction of vIRF-1 expression in a dose-dependent manner. Reduction of vIRF-1 expression resulted in higher levels of cellular interferon regulatory factor 3 and of signal transducer and activator of transcription 1. SCID mice receiving a PPMO against vIL-6 had no engraftment of PEL cells and remained healthy throughout the 120-day study. CONCLUSIONS This study showed that PPMOs can be effective antiviral agents against KSHV. Blocking the expression of early lytic genes might be beneficial for the control of KSHV-associated malignant diseases.
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Affiliation(s)
- Yan-Jin Zhang
- VA-MD Regional College of Veterinary Medicine, University of Maryland, College Park, MD, USA.
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44
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dsRNA binding characterization of full length recombinant wild type and mutants Zaire ebolavirus VP35. Antiviral Res 2012; 93:354-63. [PMID: 22289166 PMCID: PMC7114247 DOI: 10.1016/j.antiviral.2012.01.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 12/16/2011] [Accepted: 01/15/2012] [Indexed: 12/13/2022]
Abstract
The Ebola viruses (EBOVs) VP35 protein is a multifunctional major virulence factor involved in EBOVs replication and evasion of the host immune system. EBOV VP35 is an essential component of the viral RNA polymerase, it is a key participant of the nucleocapsid assembly and it inhibits the innate immune response by antagonizing RIG-I like receptors through its dsRNA binding function and, hence, by suppressing the host type I interferon (IFN) production. Insights into the VP35 dsRNA recognition have been recently revealed by structural and functional analysis performed on its C-terminus protein. We report the biochemical characterization of the Zaire ebolavirus (ZEBOV) full-length recombinant VP35 (rVP35)–dsRNA binding function. We established a novel in vitro magnetic dsRNA binding pull down assay, determined the rVP35 optimal dsRNA binding parameters, measured the rVP35 equilibrium dissociation constant for heterologous in vitro transcribed dsRNA of different length and short synthetic dsRNA of 8 bp, and validated the assay for compound screening by assessing the inhibitory ability of auryntricarboxylic acid (IC50 value of 50 μg/mL). Furthermore, we compared the dsRNA binding properties of full length wt rVP35 with those of R305A, K309A and R312A rVP35 mutants, which were previously reported to be defective in dsRNA binding-mediated IFN inhibition, showing that the latter have measurably increased Kd values for dsRNA binding and modified migration patterns in mobility shift assays with respect to wt rVP35. Overall, these results provide the first characterization of the full-length wt and mutants VP35–dsRNA binding functions.
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Roddy P, Colebunders R, Jeffs B, Palma PP, Van Herp M, Borchert M. Filovirus hemorrhagic fever outbreak case management: a review of current and future treatment options. J Infect Dis 2011; 204 Suppl 3:S791-5. [PMID: 21987752 DOI: 10.1093/infdis/jir297] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Testing an innovative therapy for filovirus hemorrhagic fever (FHF) in an outbreak setting may be years away. Moreover, beyond anecdotal evidence, little is known about best practice for outbreak case management. Currently, Médecins Sans Frontières and others provide FHF patients with basic supportive treatment. We describe and discuss treatment possibilities, challenges, and potential next steps for FHF outbreak case management. More comprehensive supportive treatment, including vital sign monitoring, intensive care components, and goal-directed interventions may contribute to improved clinical outcome; the feasibility and effectiveness of this more comprehensive supportive treatment should be assessed. Our outlined summary may assist future FHF outbreak case management teams to create collaborative platforms and develop relevant treatment protocols aimed at improving clinical outcome.
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Affiliation(s)
- Paul Roddy
- Médecins Sans Frontières-Spain, Barcelona, Spain.
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Narayanan A, Bailey C, Kashanchi F, Kehn-Hall K. Developments in antivirals against influenza, smallpox and hemorrhagic fever viruses. Expert Opin Investig Drugs 2011; 20:239-54. [PMID: 21235430 PMCID: PMC9476113 DOI: 10.1517/13543784.2011.547852] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION the search for effective inhibitors to multiple infectious agents including influenza, smallpox and hemorrhagic fever viruses is an area of active research as many of these agents pose dramatic health and economic challenges to the human population. Many of these infectious agents are not only endemic threats in different parts of the globe, but are also considered to have the potential of being used as bioterrorism agents. AREAS COVERED this review focuses on inhibitors that are currently in use in the research community against specific emerging infectious agents and those that have bioterrorism potential. The paper provides information about the availability of FDA approved drugs, whenever applicable, and insights into the specific aspect of the agent life cycle that is affected by drug treatment, when known. EXPERT OPINION the key message that is conveyed in this review is that a combination of pathogen and host-based inhibitors may have to be used for successful control of viral replication to limit the development of drug resistance.
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Affiliation(s)
- Aarthi Narayanan
- George Mason University, National Center for Biodefense and Infectious Diseases, Discovery Hall, Room 306, 10900 University Blvd. MS 1H8, Manassas, VA 20110, USA
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Leung DW, Prins KC, Basler CF, Amarasinghe GK. Ebolavirus VP35 is a multifunctional virulence factor. Virulence 2010; 1:526-31. [PMID: 21178490 DOI: 10.4161/viru.1.6.12984] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Ebola virus (EBOV) is a member of the filoviridae family that causes severe hemorrhagic fever during sporadic outbreaks, and no approved treatments are currently available. The multifunctional EBOV VP35 protein facilitates immune evasion by antagonizing antiviral signaling pathways and is important for viral RNA synthesis. In order to elucidate regulatory mechanisms and to develop countermeasures, we recently solved the structures of the Zaire and Reston EBOV VP35 interferon inhibitory domain (IID) in the free form and of the Zaire EBOV VP35 IID bound to dsRNA. Together with biochemical, cell biological, and virological studies, our structural work revealed that distinct regions within EBOV VP35 IID contribute to virulence through host immune evasion and viral RNA synthesis. Here we summarize our recent structural and functional studies and discuss the potential of multifunctional Ebola VP35 as a therapeutic target.
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Affiliation(s)
- Daisy W Leung
- Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, USA
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Geisbert TW, Hensley LE, Geisbert JB, Leung A, Johnson JC, Grolla A, Feldmann H. Postexposure treatment of Marburg virus infection. Emerg Infect Dis 2010; 16:1119-22. [PMID: 20587184 PMCID: PMC3321919 DOI: 10.3201/eid1607.100159] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Rhesus monkeys are protected from disease when a recombinant vesicular stomatitis virus-based vaccine is administered 20-30 min after infection with Marburg virus. We protected 5/6 monkeys when this vaccine was given 24 h after challenge; 2/6 animals were protected when the vaccine was administered 48 h postinfection.
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Affiliation(s)
- Thomas W Geisbert
- National Emerging Infectious Diseases Laboratories Institute, Boston, Massachusetts 02118, USA.
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Krähling V, Dolnik O, Kolesnikova L, Schmidt-Chanasit J, Jordan I, Sandig V, Günther S, Becker S. Establishment of fruit bat cells (Rousettus aegyptiacus) as a model system for the investigation of filoviral infection. PLoS Negl Trop Dis 2010; 4:e802. [PMID: 20808767 PMCID: PMC2927428 DOI: 10.1371/journal.pntd.0000802] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2010] [Accepted: 07/27/2010] [Indexed: 11/19/2022] Open
Abstract
Background The fruit bat species Rousettus aegyptiacus was identified as a potential reservoir for the highly pathogenic filovirus Marburg virus. To establish a basis for a molecular understanding of the biology of filoviruses in the reservoir host, we have adapted a set of molecular tools for investigation of filovirus replication in a recently developed cell line, R06E, derived from the species Rousettus aegyptiacus. Methodology/Principal Findings Upon infection with Ebola or Marburg viruses, R06E cells produced viral titers comparable to VeroE6 cells, as shown by TCID50 analysis. Electron microscopic analysis of infected cells revealed morphological signs of filovirus infection as described for human- and monkey-derived cell lines. Using R06E cells, we detected an unusually high amount of intracellular viral proteins, which correlated with the accumulation of high numbers of filoviral nucleocapsids in the cytoplasm. We established protocols to produce Marburg infectious virus-like particles from R06E cells, which were then used to infect naïve target cells to investigate primary transcription. This was not possible with other cell lines previously tested. Moreover, we established protocols to reliably rescue recombinant Marburg viruses from R06E cells. Conclusion/Significance These data indicated that R06E cells are highly suitable to investigate the biology of filoviruses in cells derived from their presumed reservoir. Marburg virus and several species of Ebola virus are endemic in central Africa and cause sporadic outbreaks in this region with mortality rates of up to 90%. So far, there is no vaccination or therapy available to protect people at risk in these regions. Recently, different fruit bats have been identified as potential reservoirs. One of them is Rousettus aegyptiacus. It seems that within huge bat populations only relatively small numbers are positive for filovirus-specific antibodies or filoviral RNA, a phenomenon that is currently not understood. As a first step towards understanding the biology of filoviruses in bats, we sought to establish a model system to investigate filovirus replication in cells derived from their natural reservoir. Here, we provide the first insights into this topic by monitoring filovirus infection of a Rousettus aegyptiacus derived cell line, R06E. We were able to show that filoviruses propagate well in R06E cells, which can, therefore, be used to investigate replication and transcription of filovirus RNA and to very efficiently perform rescue of recombinant Marburg virus using reverse genetics. These results emphasize the suitability of the newly established bat cell line for filovirus research.
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Affiliation(s)
- Verena Krähling
- Institut für Virologie, Philipps-Universität Marburg, Marburg, Germany
| | - Olga Dolnik
- Institut für Virologie, Philipps-Universität Marburg, Marburg, Germany
| | | | | | | | | | - Stephan Günther
- Institut für Virologie, Bernhard-Nocht-Institut für Tropenmedizin, Hamburg, Germany
| | - Stephan Becker
- Institut für Virologie, Philipps-Universität Marburg, Marburg, Germany
- * E-mail:
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