The etiological agent of the COVID-19 pandemic is SARS-CoV-2. As a member of the Coronaviridae, the enveloped pathogen has several membrane proteins, of which two, E and 3a, were suggested to function as ion channels. In an effort to increase our treatment options, alongside providing new research tools, we have sought to inhibit the 3a channel by targeted drug repurposing. To that end, using three bacteria-based assays, we screened a library of 2839 approved-for-human-use drugs and identified the following potential channel-blockers: Capreomycin, Pentamidine, Spectinomycin, Kasugamycin, Plerixafor, Flumatinib, Litronesib, Darapladib, Floxuridine and Fludarabine. The stage is now set for examining the activity of these compounds in detailed electrophysiological studies and their impact on the whole virus with appropriate biosafety measures.

Viroporins are a family of small hydrophobic proteins found in many enveloped viruses that are capable of ion transport. Building upon the ability to inhibit influenza by blocking its archetypical M2 H⁺ channel, as a family, viroporins may represent a viable target to curb viral infectivity. To this end, using three bacterial assays we analyzed six small hydrophobic proteins from biomedically important viruses as potential viroporin candidates. Our results indicate that Eastern equine encephalitis virus 6k, West Nile virus MgM, Dengue virus 2k, Dengue virus P1, Variola virus gp170, and Variola virus gp151 proteins all exhibit channel activity in the bacterial assays, and as such may be considered viroporin candidates. It is clear that more studies, such as patch clamping, will be needed to characterize the ionic conductivities of these proteins. However, our approach presents a rapid procedure to analyze open reading frames in other viruses, yielding new viroporin candidates for future detailed investigation. Finally, if conductivity is proven vital to their cognate viruses, the bio-assays presented herein afford a simple approach to screen for new channel blockers.

Genus Flavivirus contains several important human pathogens. Among these, the Zika virus is an emerging etiological agent that merits concern. One of its structural proteins, prM, plays an essential role in viral maturation and assembly, making it an attractive drug and vaccine development target. Herein, we have characterized ZikV-M as a potential viroporin candidate using three different bacteria-based assays. These assays were subsequently employed to screen a library of repurposed drugs from which ten compounds were identified as ZikV-M blockers. Mutational analyses of conserved amino acids in the transmembrane domain of other flaviviruses, including West Nile and Dengue virus, were performed to study their role in ion channel activity. In conclusion, our data show that ZikV-M is a potential ion channel that can be used as a drug target for high throughput screening and drug repurposing.

SARS-CoV-2, the etiological agent of the COVID-19 pandemic, is a member of the Coronaviridae family. It is an enveloped virus with ion channels in its membrane, the most characterized of which is the E protein. Therefore, in an attempt to identify blockers of the E channel, we screened a library of 2839 approved-for-human-use drugs. Our approach yielded eight compounds that exhibited appreciable activity in three bacteria-based channel assays. Considering the fact that the E channel is the most conserved of all SARS-CoV-2 proteins, any inhibitor of its activity may provide an option to curb the viral spread. In addition, inhibitors can also enhance our ability to understand the exact role played by the E protein during the infectivity cycle. Finally, detailed electrophysiological analyses, alongside in vitro and in vivo studies will be needed to establish the exact potential of each of the blockers identified in our study.

Mpox or monkeypox virus (MPXV) belongs to the subclass of Poxviridae and has emerged recently as a global threat. With a limited number of anti-viral drugs available for this new virus species, it is challenging to thwart the illness it begets. Therefore, characterizing new drug targets in the virus may prove advantageous to curbing the disease. Since channels as a family are excellent drug targets, we have sought to identify viral ion channels for this virus, which are instrumental in formulating channel-blocking anti-viral drugs. Bioinformatics analyses yielded eight transmembranous proteins smaller or equal to 100 amino acids in length. Subsequently, three independent bacteria-based assays have pointed to five of the eight proteins that exhibit ion channel activity. Finally, we propose a tentative structure of four ion channels from their primary amino acid sequences, employing AlphaFold2 and molecular dynamic simulation methods. These results may represent the first steps in characterizing MPXV viroporins en route to developing blockers that inhibit their function.