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Zhang T, Potgieter TI, Kosche E, Rückert J, Ostermann E, Schulz T, Empting M, Brune W. Thioxothiazolo[3,4-a]quinazoline derivatives inhibit the human cytomegalovirus alkaline nuclease. Antiviral Res 2023; 217:105696. [PMID: 37541625 DOI: 10.1016/j.antiviral.2023.105696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 07/31/2023] [Accepted: 08/01/2023] [Indexed: 08/06/2023]
Abstract
Human cytomegalovirus (HCMV, human herpesvirus 5) is an opportunistic pathogen responsible for serious disease in immunocompromised patients. Current antiviral therapies rely predominantly on drugs interfering with viral DNA replication and packaging. However, the serious side effects of existing drugs and the emergence of drug resistance indicate the need for new targets for anti-HCMV therapy. One such target is the viral alkaline nuclease (AN), an enzyme highly conserved among the Herpesviridae. In this study, we validated the HCMV AN, encoded by the viral UL98 open reading frame, as a drug target by demonstrating that a UL98-deficient HCMV mutant is severely attenuated and shows a reduced ability to spread in cell culture. We established a fluorescence-based enzyme assay suitable for high-throughput screening and used it on a small-molecule compound library. The most promising hit, a thioxothiazolo[3,4-a]quinazoline derivative, blocked AN activity in vitro and inhibited HCMV replication in plaque reduction (PRA) and fluorescence reduction assays (FRA). Several derivatives of the hit compound were tested, some of which had similar or better inhibitory activities. The most potent derivative of hit scaffold A, compound AD-51, inhibited HCMV replication with a 50% effective concentrations (EC50) of 0.9 μM in the FRA and 1.1 μM in the PRA. AD-51 was also active against ganciclovir, foscarnet, and letermovir-resistant HCMVs. Moreover, it inhibited herpes simplex virus, Kaposi's sarcoma-associated herpesvirus, and murine CMV, a mouse virus serving as a model for HCMV. These results suggest that thioxothiazolo[3,4-a]quinazoline derivatives are a new class of herpesvirus inhibitors targeting the viral AN.
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Affiliation(s)
- Tianyu Zhang
- Leibniz Institute of Virology (LIV), Hamburg, Germany; German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Germany
| | - Theodore I Potgieter
- Leibniz Institute of Virology (LIV), Hamburg, Germany; German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Germany
| | - Erik Kosche
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Saarbrücken, Germany; Department of Pharmacy, Saarland University, Saarbrücken, Germany; German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Germany
| | - Jessica Rückert
- German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Germany; Institute of Virology, Hannover Medical School, Hannover, Germany
| | | | - Thomas Schulz
- German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Germany; Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Martin Empting
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Saarbrücken, Germany; Department of Pharmacy, Saarland University, Saarbrücken, Germany; German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Germany
| | - Wolfram Brune
- Leibniz Institute of Virology (LIV), Hamburg, Germany; German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Germany.
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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 DOI: 10.1186/s12985-023-02107-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [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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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. J Ethnopharmacol 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Alam Z, Al-Mahdi Z, Zhu Y, McKee Z, Parris DS, Parikh HI, Kellogg GE, Kuchta A, McVoy MA. Anti-cytomegalovirus activity of the anthraquinone atanyl blue PRL. Antiviral Res 2014; 114:86-95. [PMID: 25499125 PMCID: PMC4289655 DOI: 10.1016/j.antiviral.2014.12.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 12/01/2014] [Accepted: 12/02/2014] [Indexed: 11/28/2022]
Abstract
The anthraquinone atanyl blue PRL inhibits human cytomegalovirus replication. The block to viral replication appears early after entry and substantially reduces viral immediate early gene expression. In vitro, atanyl blue PRL inhibits the nuclease activity of purified viral alkaline nuclease, UL98. The antiviral activity of atanyl blue PRL may be manifested through inhibition of UL98’s nuclease activity.
Human cytomegalovirus (CMV) causes significant disease in immunocompromised patients and serious birth defects if acquired in utero. Available CMV antivirals target the viral DNA polymerase, have significant toxicities, and suffer from resistance. New drugs targeting different pathways would be beneficial. The anthraquinone emodin is proposed to inhibit herpes simplex virus by blocking the viral nuclease. Emodin and related anthraquinones are also reported to inhibit CMV. In the present study, emodin reduced CMV infectious yield with an EC50 of 4.9 μM but was cytotoxic at concentrations only twofold higher. Related anthraquinones acid blue 40 and alizarin violet R inhibited CMV at only high concentrations (238–265 μM) that were also cytotoxic. However, atanyl blue PRL inhibited infectious yield of CMV with an EC50 of 6.3 μM, significantly below its 50% cytotoxic concentration of 216 μM. Atanyl blue PRL reduced CMV infectivity and inhibited spread. When added up to 1 h after infection, it dramatically reduced CMV immediate early protein expression and blocked viral DNA synthesis. However, it had no antiviral activity when added 24 h after infection. Interestingly, atanyl blue PRL inhibited nuclease activities of purified CMV UL98 protein with IC50 of 4.5 and 9.3 μM. These results indicate that atanyl blue PRL targets very early post-entry events in CMV replication and suggest it may act through inhibition of UL98, making it a novel CMV inhibitor. This compound may provide valuable insights into molecular events that occur at the earliest times post-infection and serve as a lead structure for antiviral development.
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Affiliation(s)
- Zohaib Alam
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Zainab Al-Mahdi
- Medical Science Department, College of Nursing, University of Babylon, Babylon, Iraq
| | - Yali Zhu
- Department of Molecular Virology, Immunology, and Medical Genetics, The Ohio State University, Columbus, OH 43210, USA
| | - Zachary McKee
- Department of Molecular Virology, Immunology, and Medical Genetics, The Ohio State University, Columbus, OH 43210, USA
| | - Deborah S Parris
- Department of Molecular Virology, Immunology, and Medical Genetics, The Ohio State University, Columbus, OH 43210, USA
| | - Hardik I Parikh
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Glen E Kellogg
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Alison Kuchta
- Department of Pediatrics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA
| | - Michael A McVoy
- Department of Pediatrics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA.
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