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Höing L, Sowa ST, Toplak M, Reinhardt JK, Jakob R, Maier T, Lill MA, Teufel R. Biosynthesis of the bacterial antibiotic 3,7-dihydroxytropolone through enzymatic salvaging of catabolic shunt products. Chem Sci 2024; 15:7749-7756. [PMID: 38784727 PMCID: PMC11110157 DOI: 10.1039/d4sc01715c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 04/21/2024] [Indexed: 05/25/2024] Open
Abstract
The non-benzenoid aromatic tropone ring is a structural motif of numerous microbial and plant natural products with potent bioactivities. In bacteria, tropone biosynthesis involves early steps of the widespread CoA-dependent phenylacetic acid (paa) catabolon, from which a shunt product is sequestered and surprisingly further utilized as a universal precursor for structurally and functionally diverse tropone derivatives such as tropodithietic acid or (hydroxy)tropolones. Here, we elucidate the biosynthesis of the antibiotic 3,7-dihydroxytropolone in Actinobacteria by in vitro pathway reconstitution using paa catabolic enzymes as well as dedicated downstream tailoring enzymes, including a thioesterase (TrlF) and two flavoprotein monooxygenases (TrlCD and TrlE). We furthermore mechanistically and structurally characterize the multifunctional key enzyme TrlE, which mediates an unanticipated ipso-substitution involving a hydroxylation and subsequent decarboxylation of the CoA-freed side chain, followed by ring oxidation to afford tropolone. This study showcases a remarkably efficient strategy for 3,7-dihydroxytropolone biosynthesis and illuminates the functions of the involved biosynthetic enzymes.
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Affiliation(s)
- Lars Höing
- Pharmaceutical Biology, Department of Pharmaceutical Sciences, University of Basel Klingelbergstrasse 50 4056 Basel Switzerland
| | - Sven T Sowa
- Pharmaceutical Biology, Department of Pharmaceutical Sciences, University of Basel Klingelbergstrasse 50 4056 Basel Switzerland
| | - Marina Toplak
- Hilde-Mangold-Haus (CIBSS), University of Freiburg Habsburgerstrasse 49 79104 Freiburg im Breisgau Germany
| | - Jakob K Reinhardt
- Pharmaceutical Biology, Department of Pharmaceutical Sciences, University of Basel Klingelbergstrasse 50 4056 Basel Switzerland
| | - Roman Jakob
- Biozentrum, University of Basel Spitalstrasse 41 4056 Basel Switzerland
| | - Timm Maier
- Biozentrum, University of Basel Spitalstrasse 41 4056 Basel Switzerland
| | - Markus A Lill
- Computational Pharmacy, Department of Pharmaceutical Sciences, University of Basel Klingelbergstrasse 50 4056 Basel Switzerland
| | - Robin Teufel
- Pharmaceutical Biology, Department of Pharmaceutical Sciences, University of Basel Klingelbergstrasse 50 4056 Basel Switzerland
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Woodson ME, Mottaleb MA, Murelli RP, Tavis JE. In vitro evaluation of tropolone absorption, metabolism, and clearance. Antiviral Res 2023; 220:105762. [PMID: 37996012 PMCID: PMC10843707 DOI: 10.1016/j.antiviral.2023.105762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 11/13/2023] [Accepted: 11/17/2023] [Indexed: 11/25/2023]
Abstract
Tropolone compounds can inhibit hepatitis B virus (HBV) replication at sub-micromolar levels and are synergistic upon co-treatment with nucleos(t)ide analog drugs. However, only a few compounds within this chemotype have been screened for their pharmacological properties. Here, we chose 36 structurally diverse tropolones from six subclasses to characterize their in vitro pharmacological parameters. All compounds were more soluble in pHs that reflect the gastrointestinal tract (pH 5 and 6.5) than plasma (pH 7.4). Those compounds that had solubility limits >100 μM were tested in a passive permeability assay, and there was no general trend in the compounds' passive permeability at any pH. Twenty-nine compounds with the best absorption parameters were tested in HEK293 cells to assess potential cytotoxicity; measured toxicities were similar to those in the hepatic HepDES19 cells used for screening (R2 = 0.55). Sixteen representative compounds were tested against five major CYP450 isoforms and there was no substantial inhibition by any compound against any of the enzymes tested (<50%). The t1/2 values of 15 compounds were determined in the microsome stability assay and 12 compounds were evaluated in plasma protein binding assays to assess factors affecting their rate of clearance. All compounds with detectable analyte peaks had t1/2 > 30 min, and while 4 of 12 had statistically significant decreased potency in conditions with increased albumin concentrations, only one compound's potency was biologically significant. These data indicate that the tropolones have pharmacological characteristics that reflect approved drugs and inform future structure activity relationships during drug design.
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Affiliation(s)
- Molly E Woodson
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, St. Louis, MO, USA; Institute for Drug and Biotherapeutic Innovation, Saint Louis University, St. Louis, MO, USA
| | - M Abdul Mottaleb
- Institute for Drug and Biotherapeutic Innovation, Saint Louis University, St. Louis, MO, USA
| | - Ryan P Murelli
- Department of Chemistry and Biochemistry, Brooklyn College, City University of New York, Brooklyn, NY, USA; The Graduate Center, City University of New York, New York, NY, USA
| | - John E Tavis
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, St. Louis, MO, USA; Institute for Drug and Biotherapeutic Innovation, Saint Louis University, St. Louis, MO, USA.
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Olenginski LT, Attionu SK, Henninger EN, LeBlanc RM, Longhini AP, Dayie TK. Hepatitis B Virus Epsilon (ε) RNA Element: Dynamic Regulator of Viral Replication and Attractive Therapeutic Target. Viruses 2023; 15:1913. [PMID: 37766319 PMCID: PMC10534774 DOI: 10.3390/v15091913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 09/01/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023] Open
Abstract
Hepatitis B virus (HBV) chronically infects millions of people worldwide, which underscores the importance of discovering and designing novel anti-HBV therapeutics to complement current treatment strategies. An underexploited but attractive therapeutic target is ε, a cis-acting regulatory stem-loop RNA situated within the HBV pregenomic RNA (pgRNA). The binding of ε to the viral polymerase protein (P) is pivotal, as it triggers the packaging of pgRNA and P, as well as the reverse transcription of the viral genome. Consequently, small molecules capable of disrupting this interaction hold the potential to inhibit the early stages of HBV replication. The rational design of such ligands necessitates high-resolution structural information for the ε-P complex or its individual components. While these data are currently unavailable for P, our recent structural elucidation of ε through solution nuclear magnetic resonance spectroscopy marks a significant advancement in this area. In this review, we provide a brief overview of HBV replication and some of the therapeutic strategies to combat chronic HBV infection. These descriptions are intended to contextualize our recent experimental efforts to characterize ε and identify ε-targeting ligands, with the ultimate goal of developing novel anti-HBV therapeutics.
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Affiliation(s)
- Lukasz T. Olenginski
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA (R.M.L.)
- Department of Biochemistry, University of Colorado, Boulder, CO 80309, USA
| | - Solomon K. Attionu
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA (R.M.L.)
| | - Erica N. Henninger
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA (R.M.L.)
| | - Regan M. LeBlanc
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA (R.M.L.)
| | - Andrew P. Longhini
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA (R.M.L.)
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Theodore K. Dayie
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA (R.M.L.)
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Moianos D, Prifti GM, Makri M, Zoidis G. Targeting Metalloenzymes: The "Achilles' Heel" of Viruses and Parasites. Pharmaceuticals (Basel) 2023; 16:901. [PMID: 37375848 DOI: 10.3390/ph16060901] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 06/12/2023] [Accepted: 06/15/2023] [Indexed: 06/29/2023] Open
Abstract
Metalloenzymes are central to the regulation of a wide range of essential viral and parasitic functions, including protein degradation, nucleic acid modification, and many others. Given the impact of infectious diseases on human health, inhibiting metalloenzymes offers an attractive approach to disease therapy. Metal-chelating agents have been expansively studied as antivirals and antiparasitics, resulting in important classes of metal-dependent enzyme inhibitors. This review provides the recent advances in targeting the metalloenzymes of viruses and parasites that impose a significant burden on global public health, including influenza A and B, hepatitis B and C, and human immunodeficiency viruses as well as Trypanosoma brucei and Trypanosoma cruzi.
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Affiliation(s)
- Dimitrios Moianos
- Department of Pharmacy, Division of Pharmaceutical Chemistry, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, 15771 Athens, Greece
| | - Georgia-Myrto Prifti
- Department of Pharmacy, Division of Pharmaceutical Chemistry, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, 15771 Athens, Greece
| | - Maria Makri
- Department of Pharmacy, Division of Pharmaceutical Chemistry, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, 15771 Athens, Greece
| | - Grigoris Zoidis
- Department of Pharmacy, Division of Pharmaceutical Chemistry, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, 15771 Athens, Greece
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Olenginski LT, Kasprzak WK, Attionu SK, Shapiro BA, Dayie TK. Virtual Screening of Hepatitis B Virus Pre-Genomic RNA as a Novel Therapeutic Target. Molecules 2023; 28:molecules28041803. [PMID: 36838792 PMCID: PMC9963113 DOI: 10.3390/molecules28041803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 02/07/2023] [Accepted: 02/11/2023] [Indexed: 02/17/2023] Open
Abstract
The global burden imposed by hepatitis B virus (HBV) infection necessitates the discovery and design of novel antiviral drugs to complement existing treatments. One attractive and underexploited therapeutic target is ε, an ~85-nucleotide (nt) cis-acting regulatory stem-loop RNA located at the 3'- and 5'-ends of the pre-genomic RNA (pgRNA). Binding of the 5'-end ε to the viral polymerase protein (P) triggers two early events in HBV replication: pgRNA and P packaging and reverse transcription. Our recent solution nuclear magnetic resonance spectroscopy structure of ε permits structure-informed drug discovery efforts that are currently lacking for P. Here, we employ a virtual screen against ε using a Food and Drug Administration (FDA)-approved compound library, followed by in vitro binding assays. This approach revealed that the anti-hepatitis C virus drug Daclatasvir is a selective ε-targeting ligand. Additional molecular dynamics simulations demonstrated that Daclatasvir targets ε at its flexible 6-nt priming loop (PL) bulge and modulates its dynamics. Given the functional importance of the PL, our work supports the notion that targeting ε dynamics may be an effective anti-HBV therapeutic strategy.
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Affiliation(s)
- Lukasz T. Olenginski
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA
- Correspondence: author emails: (L.T.O.); (T.K.D.)
| | - Wojciech K. Kasprzak
- Bioinformatics and Computational Science Program, Frederick National Laboratory for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Solomon K. Attionu
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA
| | - Bruce A. Shapiro
- RNA Biology Laboratory, National Cancer Institute, Frederick, MD 21702, USA
| | - Theodore K. Dayie
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA
- Correspondence: author emails: (L.T.O.); (T.K.D.)
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Schiavone DV, Kapkayeva DM, Li Q, Woodson ME, Casals AG, Morrison LA, Tavis JE, Murelli RP. Synthesis of Polyoxygenated Tropolones and their Antiviral Activity against Hepatitis B Virus and Herpes Simplex Virus-1. Chemistry 2022; 28:e202104112. [PMID: 34984767 PMCID: PMC8858858 DOI: 10.1002/chem.202104112] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Indexed: 11/06/2022]
Abstract
Polyoxygenated tropolones possess a broad range of biological activity, and as a result are promising lead structures or fragments for drug development. However, structure-function studies and subsequent optimization have been challenging, in part due to the limited number of readily available tropolones and the obstacles to their synthesis. Oxidopyrylium [5+2] cycloaddition can effectively generate a diverse array of seven-membered ring carbocycles, and as a result can provide a highly general strategy for tropolone synthesis. Here, we describe the use of 3-hydroxy-4-pyrone-based oxidopyrylium cycloaddition chemistry in the synthesis of functionalized 3,7-dimethoxytropolones, 3,7-dihydroxytropolones, and isomeric 3-hydroxy-7-methoxytropolones through complementary benzyl alcohol-incorporating procedures. The antiviral activity of these molecules against herpes simplex virus-1 and hepatitis B virus is also described, highlighting the value of this approach and providing new structure-function insights relevant to their antiviral activity.
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Affiliation(s)
- Daniel V. Schiavone
- Department of Chemistry, Brooklyn College of the City University of New York, Brooklyn, New York 11210, USA,PhD Program in Chemistry, The Graduate Center of the City University of New York, New York, New York 10016, USA
| | - Diana M. Kapkayeva
- Department of Chemistry, Brooklyn College of the City University of New York, Brooklyn, New York 11210, USA
| | - Qilan Li
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, St. Louis, Missouri 63104, USA
| | - Molly E. Woodson
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, St. Louis, Missouri 63104, USA
| | - Andreu Gazquez Casals
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, St. Louis, Missouri 63104, USA
| | - Lynda A. Morrison
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, St. Louis, Missouri 63104, USA
| | - John E. Tavis
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, St. Louis, Missouri 63104, USA
| | - Ryan P. Murelli
- Department of Chemistry, Brooklyn College of the City University of New York, Brooklyn, New York 11210, USA,PhD Program in Chemistry, The Graduate Center of the City University of New York, New York, New York 10016, USA
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Bradley DP, O’Dea AT, Woodson ME, Li Q, Ponzar NL, Knier A, Rogers BL, Murelli RP, Tavis JE. Effects of Troponoids on Mitochondrial Function and Cytotoxicity. Antimicrob Agents Chemother 2022; 66:e0161721. [PMID: 34694883 PMCID: PMC8765277 DOI: 10.1128/aac.01617-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 10/19/2021] [Indexed: 11/20/2022] Open
Abstract
The α-hydroxytropolones (αHTs) are troponoid inhibitors of hepatitis B virus (HBV) replication that can target HBV RNase H with submicromolar efficacies. αHTs and related troponoids (tropones and tropolones) can be cytotoxic in cell lines as measured by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assays that assess mitochondrial function. Previous studies suggest that tropolones induce cytotoxicity through inhibition of mitochondrial respiration. Therefore, we screened 35 diverse troponoids for effects on mitochondrial function, mitochondrial/nuclear genome ratios, cytotoxicity, and reactive oxygen species (ROS) production. Troponoids as a class did not inhibit respiration or glycolysis, although the α-ketotropolone subclass interfered with these processes. The troponoids had no impact on the mitochondrial DNA/nuclear DNA ratio after 3 days of compound exposure. The patterns of troponoid-induced cytotoxicity among three hepatic cell lines were similar for all compounds, but three potent HBV RNase H inhibitors were not cytotoxic in primary human hepatocytes. Tropolones and αHTs increased ROS production in cells at cytotoxic concentrations but had no effect at lower concentrations that efficiently inhibit HBV replication. Troponoid-mediated cytotoxicity was significantly decreased upon the addition of the ROS scavenger N-acetylcysteine. These studies show that troponoids can increase ROS production at high concentrations within cell lines, leading to cytotoxicity, but are not cytotoxic in primary hepatocytes. Future development of αHTs as potential therapeutics against HBV may need to mitigate ROS production by altering compound design and/or by coadministering ROS antagonists to ameliorate increased ROS levels.
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Affiliation(s)
- Daniel P. Bradley
- Saint Louis University School of Medicine, St. Louis, Missouri, USA
- Saint Louis University Institute for Drug and Biotherapeutic Innovation, St. Louis, Missouri, USA
| | - Austin T. O’Dea
- Saint Louis University School of Medicine, St. Louis, Missouri, USA
| | - Molly E. Woodson
- Saint Louis University School of Medicine, St. Louis, Missouri, USA
- Saint Louis University Institute for Drug and Biotherapeutic Innovation, St. Louis, Missouri, USA
| | - Qilan Li
- Saint Louis University School of Medicine, St. Louis, Missouri, USA
- Saint Louis University Institute for Drug and Biotherapeutic Innovation, St. Louis, Missouri, USA
| | - Nathan L. Ponzar
- Saint Louis University School of Medicine, St. Louis, Missouri, USA
- Saint Louis University Institute for Drug and Biotherapeutic Innovation, St. Louis, Missouri, USA
| | - Alaina Knier
- Saint Louis University School of Medicine, St. Louis, Missouri, USA
- Saint Louis University Institute for Drug and Biotherapeutic Innovation, St. Louis, Missouri, USA
| | | | - Ryan P. Murelli
- Brooklyn College, City University of New York, New York, New York, USA
- Ph.D. Program in Chemistry, The Graduate Center of The City University of New York, New York, New York, USA
| | - John E. Tavis
- Saint Louis University School of Medicine, St. Louis, Missouri, USA
- Saint Louis University Institute for Drug and Biotherapeutic Innovation, St. Louis, Missouri, USA
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Prifti GM, Moianos D, Giannakopoulou E, Pardali V, Tavis JE, Zoidis G. Recent Advances in Hepatitis B Treatment. Pharmaceuticals (Basel) 2021; 14:417. [PMID: 34062711 PMCID: PMC8147224 DOI: 10.3390/ph14050417] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/22/2021] [Accepted: 04/23/2021] [Indexed: 01/10/2023] Open
Abstract
Hepatitis B virus infection affects over 250 million chronic carriers, causing more than 800,000 deaths annually, although a safe and effective vaccine is available. Currently used antiviral agents, pegylated interferon and nucleos(t)ide analogues, have major drawbacks and fail to completely eradicate the virus from infected cells. Thus, achieving a "functional cure" of the infection remains a real challenge. Recent findings concerning the viral replication cycle have led to development of novel therapeutic approaches including viral entry inhibitors, epigenetic control of cccDNA, immune modulators, RNA interference techniques, ribonuclease H inhibitors, and capsid assembly modulators. Promising preclinical results have been obtained, and the leading molecules under development have entered clinical evaluation. This review summarizes the key steps of the HBV life cycle, examines the currently approved anti-HBV drugs, and analyzes novel HBV treatment regimens.
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Affiliation(s)
- Georgia-Myrto Prifti
- Department of Pharmacy, Division of Pharmaceutical Chemistry, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, 15771 Athens, Greece; (G.-M.P.); (D.M.); (E.G.); (V.P.)
| | - Dimitrios Moianos
- Department of Pharmacy, Division of Pharmaceutical Chemistry, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, 15771 Athens, Greece; (G.-M.P.); (D.M.); (E.G.); (V.P.)
| | - Erofili Giannakopoulou
- Department of Pharmacy, Division of Pharmaceutical Chemistry, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, 15771 Athens, Greece; (G.-M.P.); (D.M.); (E.G.); (V.P.)
| | - Vasiliki Pardali
- Department of Pharmacy, Division of Pharmaceutical Chemistry, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, 15771 Athens, Greece; (G.-M.P.); (D.M.); (E.G.); (V.P.)
| | - John E. Tavis
- Molecular Microbiology and Immunology, Saint Louis University, Saint Louis, MO 63104, USA;
| | - Grigoris Zoidis
- Department of Pharmacy, Division of Pharmaceutical Chemistry, School of Health Sciences, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, 15771 Athens, Greece; (G.-M.P.); (D.M.); (E.G.); (V.P.)
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Maepa MB, Bloom K, Ely A, Arbuthnot P. Hepatitis B virus: promising drug targets and therapeutic implications. Expert Opin Ther Targets 2021; 25:451-466. [PMID: 33843412 DOI: 10.1080/14728222.2021.1915990] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Introduction: Current therapy for infection with hepatitis B virus (HBV) rarely clears the virus, and viremia commonly resurges following treatment withdrawal. To prevent serious complications of the infection, research has been aimed at identifying new viral and host targets that can be exploited to inactivate HBV replication.Areas covered: This paper reviews the use of these new molecular targets to advance anti-HBV therapy. Emphasis is on appraising data from pre-clinical and early clinical studies described in journal articles published during the past 10 years and available from PubMed.Expert opinion: The wide range of viral and host factors that can be targeted to disable HBV is impressive and improved insight into HBV molecular biology continues to provide the basis for new drug design. In addition to candidate therapies that have direct or indirect actions on HBV covalently closed circular DNA (cccDNA), compounds that inhibit HBsAg secretion, viral entry, destabilize viral RNA and effect enhanced immune responses to HBV show promise. Preclinical and clinical evaluation of drug candidates, as well as investigating use of treatment combinations, are encouraging. The field is poised at an interesting stage and indications are that reliably achieving functional cure from HBV infection is a tangible goal.
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Affiliation(s)
- Mohube Betty Maepa
- School of Pathology, Faculty of Health Sciences, Wits/SAMRC Antiviral Gene Therapy Research Unit, University of the Witwatersrand, Johannesburg, South Africa
| | - Kristie Bloom
- School of Pathology, Faculty of Health Sciences, Wits/SAMRC Antiviral Gene Therapy Research Unit, University of the Witwatersrand, Johannesburg, South Africa
| | - Abdullah Ely
- School of Pathology, Faculty of Health Sciences, Wits/SAMRC Antiviral Gene Therapy Research Unit, University of the Witwatersrand, Johannesburg, South Africa
| | - Patrick Arbuthnot
- School of Pathology, Faculty of Health Sciences, Wits/SAMRC Antiviral Gene Therapy Research Unit, University of the Witwatersrand, Johannesburg, South Africa
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