A Novel Antiviral Strategy against MERS-CoV and HCoV-229E Using Binase to Target Viral Genome Replication

Abstract

RNA viruses cause most of the dangerous communicable diseases. Due to their high mutation rates, RNA viruses quickly evade selective pressures and can adapt to a new host. Therefore, new antiviral approaches are urgently needed, which target more than one specific virus variant and which would optimally prevent development of viral resistance. Among the family of coronaviruses (CoV), several human pathogenic strains (HCoV) are known to cause respiratory diseases and are implied in enteric diseases. While most strains contribute to common cold-like illnesses, others lead to severe infections. One of these viruses is the newly emerged (2012), highly pathogenic Middle East respiratory syndrome coronavirus (MERS-CoV) of zoonotic origin. MERS-CoV causes a severe respiratory infection with a high mortality rate of 35 %. There is no specific treatment or infection prevention available. Here, we show that the bacterial ribonuclease Binase is able to inhibit the replication of MERS-CoV and of the low-pathogenic human coronavirus 229E (HCoV-229E) in cell culture. We demonstrate that at non-toxic concentrations, Binase decreased the titers of MERS-CoV and HCoV-229E. On a molecular level, Binase treatment reduced (i) the viral subgenomic RNAs and (ii) the viral nucleocapsidprotein (N) and nonstructural protein 13 (nsp13) accumulation. Furthermore, we show that the quantity of the replication/transcription complexes within the infected cells is diminished. Thus, the data obtained might allow further development of new anti-coronaviral approaches affecting viral replication, independent of the specific virus strain.

Bacterial ribonuclease binase exerts an intra-cellular anti-viral mode of action targeting viral RNAs in influenza a virus-infected MDCK-II cells

“…Binase (secreted guanyl-preferring ribonuclease of 109 amino acid residues in the single chain; EC 3.1.27.3) was isolated from Bacillus pumilus 7p culture fluid as described before [ 18 ]. Briefly, bacteria were grown until the early stationary phase in a phosphate-deficient medium at 37 °C with agitation at 200 rpm in a Multitron shaking incubator (INFORS HT, Switzerland).…”

“…Owing to its bacterial origin, binase evades mammalian RNase inhibitors and retains its catalytic activity inside eukaryotic organisms [ 15 ]. Binase was previously shown to possess in vitro anti-viral properties against foot-and-mouth disease virus, IAV, reo- and corona- viruses [ 13 , 16 – 18 ]. In vivo, binase protected laboratory animals from rabies when it was injected into the site of viral administration and was also efficient against IAV and influenza B virus (IBV) in infected mice [ 19 , 20 ].…”

Secretome of Intestinal Bacilli: A Natural Guard against Pathologies

“…Secretion of low-molecular-weight guanyl-preferring ribonucleases (RNases) is a distinct feature of some Bacillus species ( Ulyanova et al, 2016 ). A well-studied representative of these RNases, binase from B. pumilus , has manifested antitumor ( Ulyanova et al, 2011 ; Cabrera-Fuentes et al, 2013 ; Mitkevich et al, 2013 ) and antiviral activities ( Shah Mahmud and Ilinskaya, 2013 ; Ilinskaya and Shah Mahmud, 2014 ; Shah Mahmud et al, 2016 , 2017 ; Müller et al, 2017 ). KRAS which has mutations in about 40% of patients with colorectal cancer ( Prior et al, 2012 ) was shown to be a direct target for antitumor binase ( Ilinskaya et al, 2016 ).…”

Ribonuclease fromBacillusActs as an Antiviral Agent against Negative- and Positive-Sense Single Stranded Human Respiratory RNA Viruses

“…We proposed earlier that mechanisms of antiviral activity of RNases include both the direct action on nucleic acid and indirect effects, that is, intervention into the RNA interference, immunomodulation, and induction of infected cell apoptosis (for review see [8]). We have demonstrated that binase reduced the titer of pandemic influenza A/Hamburg/4/2009 (H1N1pdm), reovirus serotype 1 (Reo 1-Lang), herpes virus type I (pseudorabies), Middle East respiratory syndrome coronavirus (MERS-CoV), and human corona virus (HCoV-229E) in infected Madin-Darby canine kidney (MDCK) epithelial cells, African green monkey kidney (Vero) cells, Madin-Darby bovine kidney (MDBK) epithelial cells, human fetal lung fibroblast (MRC5) cells, and hepatocellular carcinoma (Huh7) cells, respectively [9][10][11]. Influenza viruses contain single stranded negative-sense RNA; reoviruses have a double stranded RNA genome, while herpes virus possesses genomic DNA.…”