Mechanistic Study of an Itaconic Acid Derivative That Inhibits Nlcear Export of Nucleoprotein of Influenza Virus

Keywords: Anti-influenza A; drug discovery; itaconic acid derivatives; Michael-acceptor moiety; selective nuclear export inhibitor.Influenza viruses have caused worldwide epidemics and pandemics by reassortment and generation of drug-resistant mutants that render antivirals and current vaccinations no longer usable. An itaconic acid derivative (ITA01) was previously identified as a lead agent exhibiting anti-influenza virus activity from a chemical library of 20,800 compounds screened using a cell-based assay. Accordingly, a series of itaconic acid derivatives were designed and synthesized, using a rationale design strategy, to obtain more potent anti-influenza agents, where compound ITA07 exhibited the most potent antiviral effects, with EC50 value of 0.07 µM, in Madin–Darby canine kidney cells. Mechanism-of-action and molecular docking studies indicated that the lead agent, ITA01, acts as a selective inhibitor of nuclear export (SINE) to confine viral nucleoprotein (NP) to the nucleus by covalently binding to cysteine 528 of chromosomal region maintenance 1 (CRM1). Our preliminary data showed that ITA may possess a different mode-of-action because it also targets cysteine 119, in contrast to conventional SINEs, which target only the cysteine 528 residue of CRM1. This may reflect the antiviral activity of ITA07, which is 45-fold more potent than the known SINE verdinexor (3.2 versus 0.07 M) that has undergone a phase I clinical trial. ITA also showed good efficacy against oseltamivir-resistant viruses, suggesting its promising effect as an anti-influenza viral agent and its potential development for use against the emerging threat of an oseltamivir-resistant virus epidemic. Based on its novel antiviral mechanism with broad spectrum activity against both influenza A and B viruses, improved potency compared to the current clinical trial-tested inhibitor verdinexor, and its alternative use when oseltamivir fails, we propose to understand the antiviral mechanism of ITA07 in more detail and validate its proof-of-concept activity in a mouse model. Our aims of research are listed below.Aim 1. To improve the antiviral effects through chemically modifying the ITA analogue structure.Aim 2. To understand the protein target of the ITA compound and study its underlying antiviral mechanism.Aim 3. To evaluate the protective effects of the ITA compound in a mouse model.

Project ID:PC10907-1131
External Project ID:MOST109-2320-B182-026-MY3