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Wu CC, Chen MS, Lee TY, Cheng YJ, Tsou HH, Huang TS, Cho DY, Chen JY. Screening and identification of emodin as an EBV DNase inhibitor to prevent its biological functions. Virol J 2023; 20:148. [PMID: 37443068 PMCID: PMC10339607 DOI: 10.1186/s12985-023-02107-x] [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: 12/13/2022] [Accepted: 06/21/2023] [Indexed: 07/15/2023] Open
Abstract
BACKGROUND The Epstein-Barr virus (EBV) is a prevalent oncovirus associated with a variety of human illnesses. BGLF5, an EBV DNase with alkaline nuclease (AN) activity, plays important roles in the viral life cycle and progression of human malignancies and has been suggested as a possible diagnostic marker and target for cancer therapy. Methods used conventionally for the detection of AN activity, radioactivity-based nuclease activity assay and DNA digestion detection by gel electrophoresis, are not suitable for screening AN inhibitors; the former approach is unsafe, and the latter is complicated. In the present study, a fluorescence-based nuclease activity assay was used to screen several natural compounds and identify an EBV DNase inhibitor. RESULTS Fluorescence-based nuclease activity assays, in which the DNA substrate is labelled with PicoGreen dye, are cheaper, safer, and easier to perform. Herein, the results of the fluorescence-based nuclease activity assay were consistent with the results of the two conventional methods. In addition, the PicoGreen-labelling method was applied for the biochemical characterisation of viral nucleases. Using this approach, we explored EBV DNase inhibitors. After several rounds of screening, emodin, an anthraquinone derivative, was found to possess significant anti-EBV DNase activity. We verified the efficacy of emodin using the conventional DNA-cleavage assay. Furthermore, using comet assay and micronucleus formation detection, we confirmed that emodin can inhibit DNase-induced DNA damage and genomic instability. Additionally, emodin treatment inhibited EBV production. CONCLUSIONS Using a PicoGreen-mediated nuclease activity assay, we successfully demonstrated that emodin has the potential to inhibit EBV DNase nuclease activity. Emodin also inhibits EBV DNase-related biological functions, suggesting that it is a potential inhibitor of EBV DNase.
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Affiliation(s)
- Chung-Chun Wu
- Translational Cell Therapy Center, Department of Medical Research, China Medical University Hospital, No. 2, Yude Rd., North Dist, Taichung City, 40447, Taiwan.
| | - Mei-Shu Chen
- National Institute of Cancer Research, National Health Research Institutes, No.35, Keyan Road, Zhunan Town, Miaoli County, Taiwan
| | - Ting-Ying Lee
- Translational Cell Therapy Center, Department of Medical Research, China Medical University Hospital, No. 2, Yude Rd., North Dist, Taichung City, 40447, Taiwan
| | - Yu-Jhen Cheng
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Taiwan
| | - Hsiao-Hui Tsou
- Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Taiwan
| | - Tze-Sing Huang
- National Institute of Cancer Research, National Health Research Institutes, No.35, Keyan Road, Zhunan Town, Miaoli County, Taiwan
| | - Der-Yang Cho
- Translational Cell Therapy Center, Department of Medical Research, China Medical University Hospital, No. 2, Yude Rd., North Dist, Taichung City, 40447, Taiwan
| | - Jen-Yang Chen
- National Institute of Cancer Research, National Health Research Institutes, No.35, Keyan Road, Zhunan Town, Miaoli County, Taiwan.
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Gazquez Casals A, Berkowitz AJ, Yu AJ, Waters HE, Schiavone DV, Kapkayeva DM, Morrison LA, Murelli RP. Antiviral activity of amide-appended α-hydroxytropolones against herpes simplex virus-1 and -2. RSC Adv 2023; 13:8743-8752. [PMID: 36936842 PMCID: PMC10016935 DOI: 10.1039/d2ra06749h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 02/28/2023] [Indexed: 03/17/2023] Open
Abstract
α-Hydroxytropolones (αHTs) have potent antiviral activity against herpes simplex virus-1 and -2 (HSV-1 and HSV-2) in cell culture, including against acyclovir-resistant mutants, and as a result have the potential to be developed as antiviral drugs targeting these viruses. We recently described a convenient final-step amidation strategy to their synthesis, and this was used to generate 57 amide-substituted αHTs that were tested against hepatitis B virus. The following manuscript describes the evaluation of this library against HSV-1, as well as a subset against HSV-2. The structure-function analysis obtained from these studies demonstrates the importance of lipophilicity and rigidity to αHT-based anti-HSV potency, consistent with our prior work on smaller libraries. We used this information to synthesize and test a targeted library of 4 additional amide-appended αHTs. The most potent of this new series had a 50% effective concentration (EC50) for viral inhibition of 72 nM, on par with the most potent αHT antivirals we have found to date. Given the ease of synthesis of amide-appended αHTs, this new class of antiviral compounds and the chemistry to make them should be highly valuable in future anti-HSV drug development.
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Affiliation(s)
- Andreu Gazquez Casals
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine St. Louis MO USA
| | - Alex J Berkowitz
- Department of Chemistry, Brooklyn College, The City University of New York Brooklyn NY USA
- PhD Program in Chemistry, The Graduate Center, The City University of New York New York NY USA
| | - Alice J Yu
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine St. Louis MO USA
| | - Hope E Waters
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine St. Louis MO USA
| | - Daniel V Schiavone
- Department of Chemistry, Brooklyn College, The City University of New York Brooklyn NY USA
- PhD Program in Chemistry, The Graduate Center, The City University of New York New York NY USA
| | - Diana M Kapkayeva
- Department of Chemistry, Brooklyn College, The City University of New York Brooklyn NY USA
| | - Lynda A Morrison
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine St. Louis MO USA
| | - Ryan P Murelli
- Department of Chemistry, Brooklyn College, The City University of New York Brooklyn NY USA
- PhD Program in Chemistry, The Graduate Center, The City University of New York New York NY USA
- PhD Program in Biochemistry, The Graduate Center, The City University of New York New York NY USA
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Cao K, Zhang Y, Yao Q, Peng Y, Pan Q, Jiao Q, Ren K, Sun F, Zhang Q, Guo R, Zhang J, Chen T. Hypericin blocks the function of HSV-1 alkaline nuclease and suppresses viral replication. JOURNAL OF ETHNOPHARMACOLOGY 2022; 296:115524. [PMID: 35811028 DOI: 10.1016/j.jep.2022.115524] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 06/23/2022] [Accepted: 07/04/2022] [Indexed: 06/15/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Hypericum perforatum L. has a long history in many countries of being used as a herbal medicine. It is also widely used in Chinese herbal medicine for the treatment of infections. Hypericin, a main component extracted from Hypericum perforatum L., has attracted the attention of many researchers for its remarkable antiviral, antitumor and antidepressant effects. AIM OF THE STUDY To find plant molecules that inhibit the alkaline nuclease (AN) of herpes simplex virus type 1 (HSV-1) and suppress viral replication. MATERIALS AND METHODS Bioinformatics methods were used to determine which compounds from a variety of natural compounds in our laboratory interact with AN. By this means we predicted that hypericin may interact with AN and suppress HSV-1 replication. Experiments were then carried out to verify whether hypericin inhibits the bioactivity of AN. The Pichia pastoris expression system was used to obtain recombinant AN. The exonuclease and endonuclease activity of AN treated with hypericin were tested by electrophoresis. Immunohistochemical staining of the HSV-1 nucleocapsids was used to find out whether hypericin inhibits the intracellular function of AN. Real-time PCR and western blotting analysis were performed to test viral gene expression and viral protein synthesis. The extent of viral replication inhibited by hypericin was determined by a plaque assay and a time of addition assay. RESULTS Recombinant AN was obtained by Pichia pastoris expression system. The exonuclease and endonuclease activity of recombinant AN were inhibited by hypericin in the electrophoresis assay. Hypericin showed no inhibitory effect on BeyoZonase™ Super Nuclease or DNase I. T5 Exonuclease activity was inhibited partially by10 μM hypericin, and was completely suppressed by 50 μM hypericin. Hind Ⅲ was inhibited by hypericin at concentrations greater than 100 μM, but EcoR I, BamH I, and Sal I were not inhibited by hypericin. HSV-1 nucleocapsids gathered in the nucleus when the viruses were treated with hypericin. Plaque formation was significantly reduced by hypericin (EC50 against HSV-1 F is 2.59 ± 0.08 μM and EC50 against HSV-1 SM44 is 2.94 ± 0.10 μM). UL12, ICP27, ICP8, gD, and UL53 gene expression (P < 0.01, 4.0 μM hypericin treated group vs control group) and ICP4 (P < 0.05, 6.0 μM hypericin treated group vs control group), ICP8 and gD (P < 0.05, 2.0 μM hypericin treated group vs control group) protein synthesis were inhibited by hypericin. In the time of addition assay, HSV-1 was suppressed by hypericin in the early stages of viral replication. Hypericin exhibits potent virucidal activity against HSV-1 and inhibits the adsorption and penetration of HSV-1. CONCLUSION Hypericin inhibits the bioactivity of AN and suppresses HSV-1 replication. The data revealed a novel mechanism of the antiherpetic effect of hypericin.
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Affiliation(s)
- Kang Cao
- Department of Pathogen Biology, Chengdu Medical College, Chengdu, China
| | - Yan Zhang
- Department of Pathogen Biology, Chengdu Medical College, Chengdu, China; Department of Pathology, Fourth People's Hospital of Zhenjiang City, Zhenjiang, China
| | - Qian Yao
- Key Laboratory of Medicinal and Edible Plants Resources Development of Sichuan Education Department, Sichuan Industrial Institute of Antibiotics, School of Pharmacy, Chengdu University, Chengdu, China
| | - Yanjuan Peng
- Department of Pharmacology, Chengdu Medical College, Chengdu, China
| | - Qu Pan
- Department of Pathogen Biology, Chengdu Medical College, Chengdu, China
| | - Qiuxia Jiao
- Department of Pathogen Biology, Chengdu Medical College, Chengdu, China
| | - Ke Ren
- School of Laboratory Medicine, Chengdu Medical College, Chengdu, China
| | - Fenghui Sun
- School of Laboratory Medicine, Chengdu Medical College, Chengdu, China
| | - Qian Zhang
- Department of Nursing, The Second People's Hospital of Xindu District, Chengdu, China
| | - Ran Guo
- Grade 2019 of Clinical Medicine, Chengdu Medical College, Chengdu, China
| | - Jiali Zhang
- Grade 2019 of Clinical Medicine, Chengdu Medical College, Chengdu, China
| | - Tian Chen
- Department of Pathogen Biology, Chengdu Medical College, Chengdu, China.
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Wright LR, Wright DL, Weller SK. Viral Nucleases from Herpesviruses and Coronavirus in Recombination and Proofreading: Potential Targets for Antiviral Drug Discovery. Viruses 2022; 14:v14071557. [PMID: 35891537 PMCID: PMC9324378 DOI: 10.3390/v14071557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 07/08/2022] [Accepted: 07/11/2022] [Indexed: 02/05/2023] Open
Abstract
In this review, we explore recombination in two very different virus families that have become major threats to human health. The Herpesviridae are a large family of pathogenic double-stranded DNA viruses involved in a range of diseases affecting both people and animals. Coronaviridae are positive-strand RNA viruses (CoVs) that have also become major threats to global health and economic stability, especially in the last two decades. Despite many differences, such as the make-up of their genetic material (DNA vs. RNA) and overall mechanisms of genome replication, both human herpes viruses (HHVs) and CoVs have evolved to rely heavily on recombination for viral genome replication, adaptation to new hosts and evasion of host immune regulation. In this review, we will focus on the roles of three viral exonucleases: two HHV exonucleases (alkaline nuclease and PolExo) and one CoV exonuclease (ExoN). We will review the roles of these three nucleases in their respective life cycles and discuss the state of drug discovery efforts against these targets.
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Affiliation(s)
- Lee R. Wright
- Department of Pharmaceutical Sciences, University of Connecticut School of Pharmacy, Storrs, CT 06269, USA; (L.R.W.); (D.L.W.)
| | - Dennis L. Wright
- Department of Pharmaceutical Sciences, University of Connecticut School of Pharmacy, Storrs, CT 06269, USA; (L.R.W.); (D.L.W.)
| | - Sandra K. Weller
- Department of Molecular Biology and Biophysics, University of Connecticut School of Medicine, 263 Farmington Ave., Farmington, CT 06030, USA
- Correspondence: ; Tel.: +1-(860)-679-2310; Fax: +1-(860)-679-1239
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Ramírez-Sánchez M, Huber DJ, Vallejos CE, Kelley K. Physiological, molecular and ultrastructural analyses during ripening and over-ripening of banana (Musa spp., AAA group, Cavendish sub-group) fruit suggest characteristics of programmed cell death. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2018; 98:609-617. [PMID: 28665023 DOI: 10.1002/jsfa.8505] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 06/20/2017] [Accepted: 06/21/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Programmed cell death (PCD) is a part of plant development that has been studied for petal senescence and vegetative tissue but has not been thoroughly investigated for fleshy fruits. The purpose of this research was to examine ripening and over-ripening in banana fruit to determine if there were processes in common to previously described PCD. RESULTS Loss of cellular integrity (over 40%) and development of senescence related dark spot (SRDS) occurred after day 8 in banana peel. Nuclease and protease activity in the peel increased during ripening starting from day 2, and decreased during over-ripening. The highest activity was for proteases and nucleases with apparent molecular weights of 86 kDa and 27 kDa, respectively. Images of SRDS showed shrinkage of the upper layers of cells, visually suggesting cell death. Decrease of electron dense areas was evident in TEM micrographs of nuclei. CONCLUSION This study shows for the first time that ripening and over-ripening of banana peel share physiological and molecular processes previously described in plant PCD. SRDS could represent a morphotype of PCD that characterizes a structural and biochemical failure in the upper layers of the peel, thereafter spreading to lower and adjacent layers of cells. © 2017 Society of Chemical Industry.
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Affiliation(s)
| | - Donald J Huber
- Horticultural Sciences Department, IFAS, University of Florida, Gainesville, Florida, USA
| | - C Eduardo Vallejos
- Horticultural Sciences Department, IFAS, University of Florida, Gainesville, Florida, USA
| | - Karen Kelley
- Electron Microscopy and Bio-imaging Core, ICBR, University of Florida, Gainesville, Florida, USA
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Selective synthesis of 2-aminobenzoxazoles and 2-mercaptobenzoxazoles by using o-aminophenols as starting material. Tetrahedron Lett 2017. [DOI: 10.1016/j.tetlet.2017.09.092] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Hassan GS, El-Sherbeny MA, El-Ashmawy MB, Bayomi SM, Maarouf AR, Badria FA. Synthesis and antitumor testing of certain new fused triazolopyrimidine and triazoloquinazoline derivatives. ARAB J CHEM 2017. [DOI: 10.1016/j.arabjc.2013.04.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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A bridge crosses the active-site canyon of the Epstein-Barr virus nuclease with DNase and RNase activities. J Mol Biol 2009; 391:717-28. [PMID: 19538972 DOI: 10.1016/j.jmb.2009.06.034] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Revised: 05/29/2009] [Accepted: 06/12/2009] [Indexed: 11/24/2022]
Abstract
Epstein-Barr virus, a double-stranded DNA (dsDNA) virus, is a major human pathogen from the herpesvirus family. The nuclease is one of the lytic cycle proteins required for successful viral replication. In addition to the previously described endonuclease and exonuclease activities on single-stranded DNA and dsDNA substrates, we observed an RNase activity for Epstein-Barr virus nuclease in the presence of Mn(2+), giving a possible explanation for its role in host mRNA degradation. Its crystal structure shows a catalytic core of the D-(D/E)XK nuclease superfamily closely related to the exonuclease from bacteriophage lambda with a bridge across the active-site canyon. This bridge may reduce endonuclease activity, ensure processivity or play a role in strand separation of dsDNA substrates. As the DNA strand that is subject to cleavage is likely to make a sharp turn in front of the bridge, endonuclease activity on single-stranded DNA stretches appears to be possible, explaining the cleavage of circular substrates.
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Abstract
DNA nucleases (DNases) perform a wide variety of important cellular functions and are also very useful for research and in biotechnological applications. Due to the biological and technological importance of DNases and their use in a wide range of applications, DNase activity assays are essential. Traditional DNase assays employ radiolabeled DNA substrates and require separation of the products of the reaction from the unreacted substrate before quantification of enzyme activity. As a consequence, these methods are discontinuous. In this report, we describe a continuous DNase assay based on the differential fluorescence output of a DNA dye ligand called PicoGreen. The assay was developed to characterize a processive dsDNA exonuclease, lambda exonuclease. The assay appears to have general utility as it is also suitable for measuring the DNA digestion activities of a processive helicase/nuclease, RecBCD, a distributive exonuclease, T7 gene 6 exonuclease, and an endonuclease, DNaseI. The benefits of, and limitations to, the method are discussed.
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Affiliation(s)
- Gökhan Tolun
- Department of Biochemistry and Molecular Biology, University of Miami School of Medicine, PO Box 016129, Miami, FL 33101-6129, USA
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