Replication of human coronaviruses SARS-CoV, HCoV-NL63 and HCoV-229E is inhibited by the drug FK506

Virus Research
Volume 165, Issue 1, April 2012, Pages 112-117

Javier Carbajo-Lozoya, Marcel A.Müller, Stephan Kallies, Volker Thiel, Christian Drosten, Albrechtvon Brunn

Abstract

Recent research has shown that Coronavirus (CoV) replication depends on active immunophilin pathways. Here we demonstrate that the drug FK506 (Tacrolimus) inhibited strongly the growth of human coronaviruses SARS-CoV, HCoV-NL63 and HCoV-229E at low, non-cytotoxic concentrations in cell culture. As shown by plaque titration, qPCR, Luciferase- and green fluorescent protein (GFP) reporter gene expression, replication was diminished by several orders of magnitude. Knockdown of the cellular FK506-binding proteins FKBP1A and FKBP1B in CaCo2 cells prevented replication of HCoV-NL63, suggesting the requirement of these members of the immunophilin family for virus growth.

Keywords

SARS-CoV, HCoV-NL63, HCoV-229E, FK506, Tacrolimus, Immunophilins, FKBP1A (FKBP12), FKBP1B, (FKBP12.6), Inhibition of viral replication

Diagnostics of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) nucleocapsid antigen using chicken immunoglobulin Y

Poultry Science
Volume 91, Issue 3, 1 March 2012, Pages 636-642

A. Palaniyappan, D.Das, S.Kammila, M.R.Suresh, H.H.Sunwoo

Abstract

The goal of this study was to develop a quantitative detection system for severe acute respiratory syndrome-associated coronavirus (SARS-CoV), targeting the nucleocapsid protein (NP), to determine the presence and degree of infection in suspected individuals. Because the NP is the viral protein shed during infection and its template mRNA is the most abundant subgenomic RNA, it is a suitable candidate for developing antibodies for diagnostic applications. In this study, we have prepared full-length SARS-CoV NP expressed in Escherichia coli and purified. Full-length NP was used for the preparation of mouse monoclonal antibody and chicken polyclonal IgY antibodies for the development of heterosandwich ELISA for early diagnostics of SARS-suspected individuals. The sensitivity of the developed heterosandwich ELISA can detect the viral antigen at 18.5 pg/mL of recombinant NP. This study describes ultrasensitive ELISA using 19B6 monoclonal antibody as the capture antibody and IgY as the detecting antibody against the most abundant SARS-CoV NP antigens. One of the most important findings was the use of inexpensive polyclonal IgY antibody to increase the sensitivity of the detection system for SARS-CoV at the picogram level. Furthermore, the immunoassay of SARS-CoV NP antigen developed could be an effective and sensitive method of diagnosing SARS-suspected individuals during a future SARS-CoV outbreak.

Key words

SARS-CoV nucleocapsid protein, 19B6 monoclonal antibody, immunoglobulin Y, heterosandwich ELISA

Virucidal activity of a scorpion venom peptide variant mucroporin-M1 against measles, SARS-CoV and influenza H5N1 viruses

Peptides
Volume 32, Issue 7, July 2011, Pages 1518-1525

QiaoliLi, Zhenhuan Zhao Dihan Zhou Yaoqing Chenab WeiHong LuyangCao JingyiYang YanZhang Wei Shi ZhijianCao, YingliangWu HuiminYana WenxinLi

Abstract

Outbreaks of SARS-CoV, influenza A (H5N1, H1N1) and measles viruses in recent years have raised serious concerns about the measures available to control emerging and re-emerging infectious viral diseases. Effective antiviral agents are lacking that specifically target RNA viruses such as measles, SARS-CoV and influenza H5N1 viruses, and available vaccinations have demonstrated variable efficacy. Therefore, the development of novel antiviral agents is needed to close the vaccination gap and silence outbreaks. We previously indentified mucroporin, a cationic host defense peptide from scorpion venom, which can effectively inhibit standard bacteria. The optimized mucroporin-M1 can inhibit gram-positive bacteria at low concentrations and antibiotic-resistant pathogens. In this investigation, we further tested mucroporin and the optimized mucroporin-M1 for their antiviral activity. Surprisingly, we found that the antiviral activities of mucroporin-M1 against measles, SARS-CoV and influenza H5N1 viruses were notably increased with an EC50 of 7.15 μg/ml (3.52 μM) and a CC50 of 70.46 μg/ml (34.70 μM) against measles virus, an EC50 of 14.46 μg/ml (7.12 μM) against SARS-CoV and an EC50 of 2.10 μg/ml (1.03 μM) against H5N1, while the original peptide mucroporin showed no antiviral activity against any of these three viruses. The inhibition model could be via a direct interaction with the virus envelope, thereby decreasing the infectivity of virus. This report provides evidence that host defense peptides from scorpion venom can be modified for antiviral activity by rational design and represents a practical approach for developing broad-spectrum antiviral agents, especially against RNA viruses.

Keywords

Mucroporin-M1, Scorpion venom, Measles, SARS-CoV, H5N1, Antiviral

TACE antagonists blocking ACE2 shedding caused by the spike protein of SARS-CoV are candidate antiviral compounds

Antiviral Research
Volume 85, Issue 3, March 2010, Pages 551-555

Shiori Haga, Noriyo Nagata, Tadashi Okamura, Norio Yamamoto Tetsutaro Sata, Naoki Yamamoto, Takehiko Sasazuki Yukihito Ishizaka

Abstract

Because outbreaks of severe acute respiratory syndrome coronavirus (SARS-CoV) might reemerge, identifying antiviral compounds is of key importance. Previously, we showed that the cellular factor TNF-α converting enzyme (TACE), activated by the spike protein of SARS-CoV (SARS-S protein), was positively involved in viral entry, implying that TACE is a possible target for developing antiviral compounds. To demonstrate this possibility, we here tested the effects of TACE inhibitors on viral entry. In vitro and in vivo data revealed that the TACE inhibitor TAPI-2 attenuated entry of both pseudotyped virus expressing the SARS-S protein in a lentiviral vector backbone and infectious SARS-CoV. TAPI-2 blocked both the SARS-S protein-induced shedding of angiotensin-converting enzyme 2 (ACE2), a receptor of SARS-CoV, and TNF-α production in lung tissues. Since the downregulation of ACE2 by SARS-S protein was proposed as an etiological event in the severe clinical manifestations, our data suggest that TACE antagonists block SARS-CoV infection and also attenuate its severe clinical outcome.

Keywords

SARS-CoV, TACE, ACE2, Shedding

Synthesis, docking studies, and evaluation of pyrimidines as inhibitors of SARS-CoV 3CL protease

Bioorganic & Medicinal Chemistry Letters
Volume 20, Issue 12, 15 June 2010, Pages 3569-3572

R. Ramajayam, Kian-Pin, Tan, Hun-GeLiu, Po-HuangLiang

Abstract

A series of 2-(benzylthio)-6-oxo-4-phenyl-1,6-dihydropyrimidine as SARS-CoV 3CL protease inhibitors were developed and their potency was evaluated by in vitro protease inhibitory assays. Two candidates had encouraging results for the development of new anti-SARS compounds.

Keywords

SARS-CoV, Pyrimidines

SARS-CoV 3CLpro inhibitory effects of quinone-methide triterpenes from Tripterygium regelii

Bioorganic & Medicinal Chemistry Letters

Volume 20, Issue 6, 15 March 2010, Pages 1873-1876

Young Bae Ryu, Su-Jin Park, Young Min Kim, Ju-YeonLee, Woo Duck Seo, Jong SunChang, Ki Hun Park, Mun-Chual Rho, Woo Song Lee

Abstract

Quinone-methide triterpenes, celastrol (1), pristimerin (2), tingenone (3), and iguesterin (4) were isolated from Triterygium regelii and dihydrocelastrol (5) was synthesized by hydrogenation under palladium catalyst. Isolated quinone-methide triterpenes (1–4) and 5 were evaluated for SARS-CoV 3CLpro inhibitory activities and showed potent inhibitory activities with IC50 values of 10.3, 5.5, 9.9, and 2.6 μM, respectively, whereas the corresponding 5 having phenol moiety was observed in low activity (IC50 = 21.7 μM). As a result, quinone-methide moiety in A-ring and more hydrophobic E-ring assist to exhibit potent activity. Also, all quinone-methide triterpenes 1–4 have proven to be competitive by the kinetic analysis.

Keyword

SARS-CoV, 3CLpro, Tripterygium regelii, Quinone-methide, Celastrol, Iguesterin