I noted in your consult
@Jesse2233 that Dr Chia reported of 2 potential CVB4 antivirals, I think this study also from the Rega Institute in Belgium maybe the second antiviral he is talking about although it was targeted for CVB3 the compound proved to inhibit CVB1, CVB4, CVB5, CVB6.
http://europic2016.org/wp-content/uploads/2015/07/Programme-Europic-final_web.pdf
pg 140
THE TALE OF HOW AN IN SILICO DESIGNED COXSACKIEVIRUS B3 PROTEASE INHIBITOR TURNED OUT TO BE A CAPSID BINDER WITH A NOVEL MECHANISM INSTEAD
Rana Abdelnabi1, Ajay Kumar Timiri2, Venkatesan Jayaprakash2, Leen Delang3, Johan Neyts3, Pieter Leyssen3
1KU Leuven – University of Leuven, Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, 2Department of Pharmaceutical Sciences and Technology, Birla Institute of Technology, Mesra, Ranchi-835215, Jharkhand, India., 3KU Leuven – University of Leuven, Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, B-3000 Leuven, Belgium
OBJECTIVES: An in silico molecular docking study on the Coxsackievirus B3 (CVB3) 3C-protease guided the synthesis of a novel benzene sulfonamide derivative (i.e. compound 17) that was shown to inhibit the in vitro replication of CVB3. Our aim was to use virus-cell-based assays to con rm the 3C-protease as a target for the compound and to study the particular characteristics of its antiviral activity.
METHODS: Cell-based antiviral assays (CPE-reduction, virus yield and plaque assays) and molecular biology tools (reverse-engineering, RT-PCR and sequencing).
RESULTS: Compound 17 proved to inhibit the in vitro replication of CVB3 (strain Nancy) as well as of CVB1, CVB4, CVB5 and CVB6 with EC50 values ranging between (0.7-37) μM. Surprisingly, the compound did not show any antiviral activity against CVB2 and other viruses from different enteroviruses groups. In contrast to what is expected for a protease inhibitor, a time-of-drug-addition study pointed out that compound 17 interfered with an early step in the CVB3 replication cycle. A thermo-stability assay provided an additional indication of an interaction between compound 17 and the CVB3 virus particle. This latter mechanism of action was con rmed by the genotyping of independently selected compound 17-resistant CVB3 variants, which all carried mutations in the VP1 gene (F76C, E78G, A98V and D133G). Compared to the wild-type (WT), the reverse-engineered VP1 F76C, E78G, A98V and D133G mutants proved to be 18, 21, 3 and 38-fold less sensitive to the antiviral effect of compound 17, respectively. Interestingly, the mutated VP1 residues are located outside the common drug-binding pocket for capsid binders such as pleconaril. Moreover, the D133 residues of all ve VP1 units are arranged in the form of ion channel at the 5-fold axis. Plaque phenotyping revealed that the VP1 F76C, E78G and D133G mutations resulted in a smaller plaque size than WT.
CONCLUSION: Compound 17, originally designed in silico to inhibit the viral 3C-protease, is a potent inhibitor of CVB3 replication. Surprisingly, study of the mechanism of action revealed that the compound is a capsid binder with an entirely new target on the virus particle. Further experiments are ongoing to explore the precise mechanism by which compound 17 interacts with CVB3 capsid and to develop more potent and broader-spectrum analogs.